Someone said, "The winner of a knife fight is the one that makes it to the hospital" Avoid it when possible, also don't try to do anything fancy you see in movies. I once talked to a veteran who said slice attacks won't do any good if both are prepared to fight (common in knife fights) the best way is to stab them multiple times at vitals like chest and throat (I'm not sure if India has the "excessive force" law though) and gut when you get a chance. Stabbing them in shoulder multiple times is good too. Almost any knife would work except those "10 rupiya" knives. The most important thing about knife fighting is to stay fit, so going to gym or a little bit of exercise at home would help.
When I'll get to shoot a gun?