Cover Me!
Cover me! I must have heard that line a thousand times, but never really understood what it meant until the first time I played paintball. Suddenly I realized I had no idea how to cover anybody!
Giving cover means to stop you opponent from shooting so your teammate can make a move. How do you stop your opponent from shooting? Harsh language, a note from home perhaps? Of course not, we shoot at them!
Here's cover fire in a nut shell.....
Communication
If you're the one providing cover for your buddy make sure you know what you need to shoot at, if you're not sure ask him. There may be more than one person who can shoot at him, more than one threat, so you need to know who he'll be shooting at and who you'll be shooting at. If you're the bold one making the run make sure he knows where he needs to shoot.

Yes; It's a Paintball Field
Be careful when you're planning, don't look at the person you are talking to, keep your eye on the game while you talk, communicate verbally, avoid pointing. Don't say "over there" and point, say "behind the whatever", better yet take a shot at it. Shooting something clears up any confusion about which tree you're talking about real quick.
The runner should check with his cover to make sure you are both ready, when the coast looks clear the runner says he's going. The runner should always be in control, it's his butt on the line. Act as a second set of eyes for the runner, if you see something that's going to get him shot let him know.
Shoot, a Lot!
Have your gun on target while you wait for the runner's go signal. Once the runner tells you he's going start shooting as fast as you can, don't wait for him to start running, just shoot and don't stop shooting until he's safe. Aim carefully, make sure you push the bad guy down so he can't get off a shot.
Watch as Rick and I plan and execute a quick move just like I described above. A quick con-fab to decide who was running then he starts blasting to keep the bad guy down and I take off. It’s great if you can hit the guy like Rick did here, but if not just keeping your runner safe is enough.
That's it! Like snap shooting this should be something you do every time you play, not a strategy you dust off once in a while. Need practice as the runner? The end of the game is the perfect time to practice, worst case you miss the last 30 seconds of the game, best case you bust it wide open!
If you watch speed-ballers from a distance you will see that almost all of their fire is suppressive fire. Sometimes they are covering for a teammate(Cover fire), others to keep themselves safe (Hiding Behind Thier Guns), still others are trying to stop opponents from making it to a bunker (Laning), but in the end it's all suppressive fire.