Tactics

A single person can have tactics by himself. These are of the few things a person can:

Efficiently fire. 

Take out the enemy quietly.

Moving.  

In Airsoft I generally like to fire in 3 round bursts, that way you can keep up with the Mag feeding. (If you have a Hi-Cap)

From time to time I'm sneaking up on an enemy and I can't afford to be noticed. So what do you do about footsteps? Well when sneaking I generally put my heel down followed by the rest of the foot. It will help keep you quiet.

The third and final is the most important. Moving you've probably heard this before but the more the better.

Stay behind cover! When moving you never know when an enemy pops his head up and starts firing. also unless you get hit, keep your rifle upraised. keep scanning for enemy. When running across long distances without cover move slowly. Fast movement attracts human eyes. If you move fast someone could spot you or a sniper could see you. you don't want that!