For snake, I normally just practice diving. After that, find different ways to move when you are bumping. Go slow, find out what feels good, what is correct, and how low you are. Get faster.
Have 2 players stand a distance apart (like 1/2 way to the 50 on each side). Have 1 player shoot at the other, and the second players has to dodge. This can help with reaction time.
Do snap shooting drills with a team mate.
Run 2v2's, run 1v1's
A 1v1 drill that can help with playing anyway is doing a 1v1 off the break. When one of the players gets shot, the game pauses, they walk out and the other stays in. Someone replaces the eliminated player in the same bunker he was in. Basically, you're playing King of the Hill, but the "Hill" is staying in for as long as you can.
For laning, have someone run through your lane. That's it. They can have a ref shield or whatever to start out if they don't want to get shot up or to give you a bigger target if needed.
Running and Gunning:
http://www.youtube.com/watch?v=XlQc9BVQsVs
