Most martial arts are bunk unless you are fighting someone who has no idea how to fight. IMO the best things to learn are ground fighting and combine that with boxing and I would also learn some judo for takedowns.
agree with this post, i think actually fighting comes naturally to people or just from having alot o fights on the first place.
I think the best way to prepare your self for a fight is the do cardio and train on a boxing bag a few times a week, learn to do some kicks i guess, but mostly learn to guard your self with your legs. Im my opinion what ins fights in the ability to actually fight, cardio and then size.
Best thing to do however is avoid fights altogether, since you never know who you are up against.