The knife is a very skillful and stealthy weapon to use in Counter-Strike. When starting out in a round, take it out and run towards the enemy with it. The knife is light, so you will run faster. Also, for very upclose attacks, take it out when an oppenent is reloading right near you, and stab him or repeatedly slash 'em. In knife fights, a good tactic is to crouch, wait for enemy to approach you, then right when he comes up to you, jump in the air and stab him at the head. This usually if done correctly will just about kill em.