This guide will help you with specific situations.
Timing Your Reload
If you start shooting at somebody, you might hit them once or twice. Use a few bullets from your current weapon and if your enemy doesn't die, switch to another and shoot as you run back (or rush in if you have the confidence because your enemy might be reloading). Don't reload unless you have a decent distance and cover from your enemy.
If you know there is an enemy close by that probably hasn't heard your footsteps, don't give away your position by reloading your weapon (unless your clip is very low). Continue to be stealth and wait until you hear their footsteps again, then take action.
Baiting Your Teammates
Baiting is basically holding your position while your teammate(s) enter an area. Baiting your teammates isn't a nice thing to do but when you're low on health it will help you stay alive. When you bait, make sure you keep an eye on your radar, so you know where your enemy is located. Hopefully, your teammate will spot more than one (if there is more than one). If your teammate dies you should at least get one since you know their position.
Remember, baiting isn't nice! Try to minimize this tactic for only when you have low health.
Multiple Enemies
Sometimes you will find yourself rushing into an area where there are more than one enemy. If you do this, make sure you focus your crosshair on one at a time. If you start to shoot at one and quickly switch to the next one, you'll end up getting killed without killing anybody, make sure you at least take one with you for your trouble. The best way to avoid handling multiple enemies is to never rush into an area. Try to pick them off by the doorway or behind cover, so you can back up for cover.
If you find yourself with a group of enemies running toward you, you can try to run or you can just spray until you die. If you do try to run, sometimes you won't be able to make it in time. If you crouch and spray for your life, you might be able to take one or two with you (if you're lucky).
Going Against the AWP
To win against an AWP, you must first notice the AWPer or try to guess where they are. When you come to a point where you run into an AWPer or think an AWPer is around the corner, stick your body out a little bit and pull back as fast as possible. Once you here the AWP fire, rush out and try to get a headshot before the AWPer gets the chance to take aim. If the AWPer sees multiple enemies, he will run back and find the next AWPing spot available. Keep this in mind and don't rush in, simply repeat the same steps as before.
Going against the AWP is no easy task but if you practice on getting quick headshots, you will have little to no problem.
