Help? Any fighting tips?

Hey, i don't want to come across as a caveman looking for fights. I'm just looking for some tips on how to win a fight, knock somebody out, some self defense moves and how to control the 'fight or flight' feeling. Theres this guy who always gives it 'beef' and it's just annoying me, he always tries to show off etc. He wants to fight me and i'm looking for some new fighting tips and all of the above if possible. At my Primary School i occassionally got into brawls or fights with other students because i had anger issues but all thats changed now, i do get angry but not as easily. This guy is not tall but has alot of power, mainly to do with his weight in my opinion. But i'm quite tall and work out 2-3 times a week. i'm not sure if he works out thought. any answers for the above? thanks, any answers I will appreciate :D