Here's my advice, this will help you get on your feet much more quickly than I did
First... Create your own server, and kill bots for a while. Set the bots to have no weapons, just knives. If you try to play in a real server at first you'll just die and never learn anything. You need to learn how the guns work. Just try killing weaponless bots with the pistols at first - usp for CT's and glock for T's.
On the topic of learning the guns... in your own private server, buy a gun, and just spray a full clip straight at the wall. Watch where the bullets go - it might surprise you!
Now shoot off another full clip at varying speeds, watching how quickly you can shoot without having the recoil affect the bullet spread too much. You need to keep this in mind while playing, because if you start shooting quickly the bullets won't go straight - they generally go up, and you need to compensate. This is why many people will recommend spraying at about the waist level, if you're going to spray.
Also on the topic of guns and shooting - don't move when you shoot. Try shooting a single AK shot at a wall while standing still, and then try it while running forwards. Notice how horribly innacurate the shot is while you're moving. If you expect to hit anything with a rifle, stand still while shooting. You can move with pistols and SMGs to some extent, but you generally want to be standing still when taking shots.
Never use the AWP - it's too easy to get kills with, and if you start using it while you're still a noob you'll develop bad habits. Once you're good enough to go into a pub and consistantly get KDR's of 4:1 or better you can start awping, and it'll just make you that much better
You'll find it's easy to get kills with the awp, but it's very hard to be a good awper. Not that being a good awper matters in a pub - all you have to do there is kill people.
Next, never over-commit. I used to do this all the time. In a pub, staying alive should be priority number 1. The longer you stay alive, the more you'll learn and the more fun it will be. It's no fun if you try to run across an open stretch at the beginning of the round and get AWP'd, and then have to wait 3 minutes for the round to end. In most situations, you don't need
to rush or anything, so take your time. Never run into things hastily unless you know what you're doing, because you'll die - it's better to live and fight another day.
Here's the big secret to CS that no one will tell you.... The key to CS is not being a moron. It may sound simple, but 99% of people who play in pubs play like morons - don't be one of them, and you will go far
The biggest way morons die in pubs is peeking known awpers. If somebody runs across an opening and you watch him get AWPd in front of you... go the other way
It's incredible how many people will still try to cross after seeing their teammate get killed. Or, you can throw a smoke grenade and then cross if you have enough time.
Also, don't try to take out an AWPer with a pistol or smg. Don't even try it with a rifle unless the guy is terrible and you're sure you can take him out before he can take you out. Your best bet is probably just to avoid awpers alltogether while you're learning. Trying to take down an awper will probably just end with you dying a quick death, and having to sit the rest of the round out.
Never follow your team in a pub. Like I said before 99% of pub CS players are morons, and if you follow them around, they will rub off on you
Often somebody will say before a round "lets all rush A", when realistically having more than 2-3 people going that way is pointless because the other 10 people won't do any good. You'll just get flashed, and 10 people will die instead of 2.
If your whole team goes one way, go the other way by yourself and play smart and conservatively. There are many benefits to this - you'll prevent your teammates from getting flanked (because of course none of them will be watching for it, because in all likelyhood they're idiots). The other team will also not be expecting you to be going where you are, so you'll have the element of surprise on your side (hopefully). Take it slow, walk, don't give yourself away till you have to, because no one will be expecting you and you want to capitalize on that. Going the other way also gives you a good opportunity to flank the enemy team if you want. You have to be very aware of what's going on around you though, as you'll be on your own.
One more thing on the topic of not being an idiot... don't stand still. I know I said earlier to stand still while taking shots, but this doesn't mean remain still. Strafe out from behind cover (you should never be out in the open without cover or somewhere to hide), stop quickly by hitting strafe in the opposite direction, take your shot(s), and then move again. Some people will crouch because crouching helps reduce recoil, but those people are idiots. Don't crouch, it'll just make you a sitting duck. Any player worth his salt will hit a crouched player every time (then again, most players aren't worth their salt so it works better than it should in a lot of circumstances).
I hope that helps you a bit. To recap... When you're starting make a server and just kill bots to get a feel for things. Spray a whole clip at the wall so you can see how recoil works as it's a lot different than many other FPS's. Don't overcommit, and don't be a moron
Also, never talk ****, ever. Even if you're dominating, never comment on how bad the other team is. Only speak positively. Say "nice shot" if you get owned, etc. If you feel the need to make fun of the other team, do it in team chat so they can't hear. Sportsmanship is really important (at least to me) - especially since no matter how good you are, there's always somebody 100x better.
Oh, and never accuse anybody of hacking unless you're sure of it. A lot of people do hack, but most of them are so bad that it doesn't really help them much
Let the more experienced people worry about it, because if you're new there is a tendency to say "**** hax!" every time you get killed. It's better if you just believe hacks don't exist and that guy is just really good. When you think somebody else is hacking it makes it somehow "ok" that you die to him, and takes away any ambition of playing well.
...ramble ramble, I could go on forever about this game