How not to be a newbie

1. Moving Around:

1a. vehicles
do not jump onto or into a moving vehicle. you will die. (this is a CS 1.4/1.5 bug)
do not crouch or jump when you are in or on a moving vehicle. the driver will lose control and the vehicle will stop (CS 1.4/1.5 bug)
do not drive if you don't know how or you don't know your way around the map - leave it to someone who does and practice on your own
if possible, look at your team when you "start the engine" and make sure no one is getting on before you move. otherwise they will die if they are jumping on as you leave, and if tkpunish is on, you will have to sit out a round

1b. ladders - going up
always crouch when going up ladders. it's almost silent, you are a smaller target, and it doesn't slow you down. if you have to be completely silent, just crawl a few feet at a time by tapping the up key - this is hard to do though. (fm)
always leave 2-5 feet between you and a guy above you as you climb. if you are under him when he reaches the top, you will both get stuck there, he in midair above the top of the ladder
when getting off ladders - up or down - be careful because if you are moving sideways when you go off, the ladder will accelerate your sideways movement. this can help you evade fire, or cause you to fall and die. you can also save a little time by jumping at the base of the ladder or falling the last 10 feet to the side. with practice you will determine how far you can fall without taking damage. (db)

1c. ladders - going down
if you have trouble descending a ladder off a ledge, try facing the edge and crouch-walking off the ledge while looking straight down. if you walk off, you will fall and die, and if you look forward even 45° you might climb into mid-air, and fall to your death.
If it's a very long ladder, you can make a super-speedy descent by falling off the top and moving back to the ladder before you hit bottom. this can be dangerous though.

1d. running
always run with knife out away from spawn. learn how far you can go before an enemy can get there, and keep your knife out until you are almost there.
always run with knife if you are certain there wont be enemies popping out in the next .5 seconds.
always run with knife if bomb timer reaches 20 and you are 10 seconds away with no kit.
always run with knife when you have a teammate running a second or two in front of you - he will get attacked first.
when in doubt, run with knife. Get in the habit of popping your knife out even for 1/2 second when you know you will be safe. Just hit 1 for your primary weapon and don't click, and it will be ready to fire with a click to get it out. (vlv)

1e. speed
speed is essential. many, many kills and victories will be the result of moving faster than the other team thinks you can move. this is why some rushes work - whoever reaches a location first has an advantage over others. speed is also very important because it is a timed game. if you can get from A to B in 7 seconds instead of 8 seconds, you have an advantage. the only way to go faster is to have your knife out. other than that it comes down to knowing the best paths around the map.
01/02 Addition - a clarification by ezykill lol - when you pikc your knife, you should hit the 1 or 2 button and not hit fire so the weapon is ready to go with 1 click of the mouse (as opposed to not hitting the 1 or 2 key until you are ready to shoot, which would delay you too much). of course this doesn't apply to you if you use fastswitch.
01/02 Addition - Several people have asked if pistol is really better to carry than knife. The pistol just makes you 1% slower than knife - but that tiny bit means you win a 100m race by about 3 feet, which is fast enough, for example, to get into the middle bombsite on de_dust before the enemy gets around that last corner, giving you a fraction of a second advantage. In CS that's all you need.
01/02 Addition - In small games (e.g. 2v2 to 5v5) often speed is less important than sound. Use walk or crawl to be silent if you don't have a bunch of teammates with you, and don't try to rush unless the whole team is going with you.

1f. silence
if you are vastly outnumbered, the advantage of speed will be lost, and your only other advantage is surprise. under these conditions, speed is less important than silence. try to find a silenced weapon on the ground like a TMP, USP, or a colt, and wear out your walk/crawl key.
however, if you only have 30 seconds left to rescue or defuse, you should forget silence and weapon shopping and just run for it.
01/02 Addition If you are coming up behind a teammate who is walking, it behooves you to walk as well for two reasons: a) he might be sneaking up on someone and b) it's rude to give his position away. If you are in a hurry to get somewhere, run past him and try to distance yourself from him as quickly as possible. Do not just run in place behind someone who is walking!

1g. water and ladders = no fall damage
you can fall from *any height* and land with no damage on a ladder or water surface. this has non-obvious consequences. example, on cs_alpin you can fall 200 feet and land safely on a rope ladder far below. on cs_5star you can fall from the top of the building and land safely in the wading pool.

1h. team coordination
many maps have routes or locations that are only possible to reach with teamwork. for example, you can boost a teammate to the ladder on de_vertigo for a shortcut. pay attention to tall ledges and boxes and whenever possible suggest them. be sure to offer or provide help to others to reach them. (db)

2. Combat

2a. friendly fire
do not shoot or stab people for fun even when FF is off. it annoys them and makes noise, and it's a bad habit to have when the admin turns on FF because it will make you look like an ass when you shoot someone at the start of the round.

2b. knife fighting
in a 1 vs. 1 knife fight, always right click (exceptions noted below). it takes 2 x as long but does 4.5 x damage.
right click (alternate) knife attack has about 2 foot range, left click has about 5 foot range. see:

(pics from summerblue CS Report - link at the bottom of the page)
note - according to McCaffrey of CS Nation, the primary attack knife range was reduced in CS 1.4/1.5 so take these images with a grain of salt until I do some testing.

in a mass knife fight, you may sometimes use left click because it has a large area of effect - a left click attack doesn't require accuracy. when using left click, aim for the head if you can. it will add 4 to damage.
against a newbie player, just run up and right click and drop back. against a good player, jump and knife downwards with right click to try for a 1-hit headshot (bls) (I've seen knife hits that did 260 damage). against an expert, just dodge constantly and don't let them get close. use your left click longer range attack and try to whittle them down before they get 2 alternate hits in and kill you.
if you want to be found, knife a surface (e.g. wall/floor) to announce your position - it makes the louder knife attack sound.

2c. teamwork
if you play RPG's you know that 3 guys against 2 will do more then 3/2 of the damage, because they will more quickly increase their odds. it's the same in CS. 2 guys are more than twice as deadly as a single guy alone. take advantage of the math factor.

2d. awareness of teammates
if you see a teammate camping on your side behind a door, don't run through the door to secure the room beyond, making his position pointless. you can use him as a trap - try to draw the enemy through the door so he can kill them easily.
if you see a teammate hiding somewhere, do not go start knifing him, and do not draw fire to him by being noisy or standing in plain sight next to his hiding spot. if possible try to distract enemy units in such a way that he can fire at them.
if you are running in front of a friendly group and you see an enemy to the side, run past him fast. odds are he will turn to fire at you and your teammates will shoot him in the back. if you instead stop to shoot him, the whole group behind you will be slowed, and you might lose the fight anyway.
if you see a teammate under fire, DO NOT wait for him to die before you jump out to finish off the reloading and weakened enemy. this is safer for you but reduces the force multiplier effect. if you helped him sooner you would killed the enemy sooner, you might have distracted the enemy, and you might have absorbed some of the damage, so the total damage to the enemy would be lower. your grateful teammate might protect you in return next time, too.
when guarding a route with a teammate, spread out but stay in visual or audio contact. you will be much more effective if you are on the other side of the room. if you are right next to each other, the enemy can kill both of you almost as easily as killing one.
if you see a teammate camping, think about their weak spot - to one side or behind them. then pick a spot to guard where he can cover your weak spot and you can cover his. two people working together like this can kill a dozen enemies. a good example is crouching under the trains on de_train - one player on each end facing each other.
if a teammate is popping out from cover to shoot someone, don't run into his old position. he might be expecting to drop back into it to reload, and if you are in it he will die.
if you see someone on your team sniping, try to stay out of their line of sight (maa)
if you are rushing with teammates down a narrow passage (like sewers in cs_militia), stick to the outside wall farthest from where enemies will appear. it will make you visible to enemies sooner, but your whole team won't be hitting you in the back if he pops out.

2e. rushing
the points of rushing are that you move fast (obviously), and that you move the force of your team from point A to point B rather than dispersing it through the map (more important). it can be helpful to get to a location before the enemy (thus "rushing") but more it's important to have the maximum number of people together. if 3 enemies are defending a bunker, if you run in with 5 guys you will kill them. if you send in 5 guys in, 1 at a time, you will might kill 1 of them if you are lucky.
when your group rushes, it's natural that the first few people will die. they should expect this to happen. even if they inflict no damage, hopefully they caused at least one enemy to run out of bullets. if the rest of your group completes the rush, the enemy will be helpless. however, if everyone behind you is shocked at your gruesome death and stops rushing, or you backtrack and try to stay alive, your rush will have been wasted. KEEP MOVING is the foremost principle here, and key for the frontmost positions.

2f. watch the clock and goals
if it's 1 minute into the round and bombsite A is empty, you should probably fall back to the other site (as long as at least 1 person stays there to guard the site). likewise, if you took a slow and careful route to the hostages, be sure you leave yourself enough time to rescue before the clock runs out. if the C4 timer is 35 seconds, and the clock is 35 seconds, obviously you can stop guarding the bomb and instead just hide because if you live, you win. if you are the last T, and you know they are going to rescue all the hostages and you can't stop them, you should kill yourself, thus denying their team the massive funds from rescuing (exception - if you have an expensive weapon you want to keep, and you are a selfish bastard).

2g. communicate enemy positions
if your team has 1 enemy left, and you see his location, it's more important to tell your team where he is than to try to kill him yourself. I've often seen a single player kill 4 or 5 enemies and win the round because the enemies didn't bother to send a simple radio message and wait for backup

2h. bullet penetration
bullet penetration is based on BSP Blocks. these are invisible units of segmentation built into the BSP file when it is compiled. you can get bullet penetration on a wall 50 feet thick, if the map happens to compile that way.
note that invisible surfaces, like the space between ladder rungs, have the same blocking quality as a wooden crate. if you are standing next to a ladder and someone is chasing you, move behind it, and you will take decreased or no damage
the deagle, all rifles, and the para are the only weapons that can penetrate objects.

2i. aiming
most people know that if you are in midair, the CS engine will make your shots inaccurate. ladders have the same effect - as tempting as it is to hid at the top of a ladder, your aim will be very bad. for example, AWP shots will never hit where they are supposed to. do not camp on ladders.
when playing on a server with low gravity, stay on the ground and your aim will be much better than the aim of everyone in the air. if you have to be in the air, buy a shotgun, because both shotguns aim normally when in midair - however, they do not fire when underwater.

2j. spacing
it's important to coordinate and move together, but don't get spaced too tightly. the players in front should have room to fall back behind their teammates to reload or avoid an HE grenade (their own or the enemy's).

2k. dropped weapons
if you have an MP5 and you see a colt or AK on the ground, pick it up (unless you are being shot at). be ready to reload it if necessary. same with glock vs. deagle, or whatever your favorite weapons are.

2l. cover and concealment
a dimly-lit spot is better than a well-lit spot. you can tell if you are deep in shadows if your gun turns black (unlit).
if there is any chance someone saw you hide, bite the bullet and run back out. if they saw you, they won't expect you to come out and you can get the drop on them, but you're dead meat if you sit there.
use a smoke grenade in the middle of a large area about 5 seconds before you run through it. it can also be a good distraction - throw it then go a different way.
01/02 Addition - a very good point by Fusionfury: when you are camping behind a box and expect people to run by, dont face parallel to the side of the box. face about 20-45 degrees inward so the tip of your rifle is covered by the box.

01/02 Addition 2m. using sound
(by Pablo)- if you want to do better (and you have 4 speakers), turn up your sound and then compare it to your radar (to make sure it isnt a teammate). example: on dust, plant the bomb around a corner or in front of a door, and then hide nearby, not leaning out to see if someone is coming. when you hear them start to defuse, rush out and you should know exactly how many people there are and approx. where they are, and can even shoot through the box or door if you know precisely where they are.
also use sound against the other team. example: on assault i was the last ct left and i had dropped down from the vents in front of the hostie room. i knew the 2 ts left where outside looking for me, so i selected the hosties and moved them out in front of the cameras. then i went out the small side exit and dropped down behind the big red crate. because the hosties make so much *&$*ing noise when you select them, the ts rushed back in to kill me, but i nailed them in the back as they passed through the garage door. basically i was giving the other team false information.

01/02 Addition 2n. improving your game
(by Pablo)- dont use cs to get good at cs. play more realistic games like operation flashpoint and rainbow 6 to get a better understanding of how to maneuver around and trick the other team. cs tends to make people rush out guns blazing, when you should be sneaking around from box to box. there is no feeling greater than killing 6 cts on militia as the last t left because they ran around alone while i moved silently, killing them off one at a time.

3. Half-Life engine:

3a. radar
the radar will turn itself off sometimes. the only way to fix is it to wait (it may come back in after 5 mins), or restart CS. the drawradar command will not fix it.

3b. disappearing players
the HL Guard cheat detection has an occasional bug that makes people disappear (actually they appear 50 feet above where they are). this usually goes away as soon as you are dead. if you can tell there are "invisible" enemies around, retreat and wait for the problem to go away

3c. wrong logos/sprays
if the server has download on, you cache everyone's logos. sometimes your index can get messed up temporarily and you will spray someone else's logo. it will get fixed if you restart or wait a while.

3d. bullet penetration
bullets that don't penetrate will look like they penetrate. don't assume that because you can see bullet marks around the corner that you will damage people there

3e. map errors
sometimes servers don't load a map correctly and something will be wrong. a ladder won't work, you won't be in a buyzone at start, or a wall will be missing. just wait for the map to change (or find an admin to change it) and it will go away.

4. Attitude:

4a. when you die
do not say "BS" "wtf" or otherwise imply that you were robbed. you died. accept it. if dying upsets you, CS is the wrong game for you.
if the death was tragic/painful/humiliating, you can say something to express it:
- a joke ("that's going to leave a mark")
- a mocking insult ("I hate you, I really hate you")
- a compliment ("nice shot")

4b. detecting cheaters when an admin is present
if you think someone is cheating, DO NOT start yelling to everyone about it. you just made the admin's job a lot harder, and if not, you are just making everyone feel cheated.
wait for a moment when only the admin will hear you, or at least as few people as possible, and let him know. don't be angry, just state the facts ("I saw H4X0R turn 180 and shoot 2 guys instantly") then shut up and let him do his job. do not bother him about it again. do not complain to everyone on the server, and for god's sake don't keep saying "H4X0R CHEATS! BAN HIM!" over and over, because that will just make him leave and change his name. the admin needs a few minutes to confirm a cheat, and if he leaves he can't be positively identified.

4c. detecting cheaters when no admins are there
the first principle is, don't make the situation worse. that means don't whine about it to everyone over and over. either ignore it, leave, or follow these instructions:
- record a demo. making a bunch of short demos is better than a long demo. then you can watch them later and pick the best 2-3 to prove your case
- take screenshots of anything he says that is suspicious
- post on the server forums with your evidence
the point is, just because he is ruining the game for you, doesn't give you the right to ruin it for everyone else
if the server doesn't have forums, or the admins don't welcome your vigilance and attempt to be helpful, find a new server