If you don't want to lose a lot of health by fighting a guy the old fashioned way here's what you do. Grab the guy(using the square and X buttons I think) and throw him against a wall. Then start punching as hard as you want as he won't be able to move!! Hope it helps.

When you are fighting someone and they have a weapon e.g gun, chair, bottle, you can use your whip to snatch small items (guns, bottles) out of their hands and then you can pick them up and use them.

If your enemy is using a chair you can break it before he hits you with it!