In self defense, what is the best way to defend yourself against a taller person

I believe eventually this guy at my school will eventually try and start on me. I am broader than him but im about 5-7inches smaller. He is 6ft4 and I a 5ft10 roughly. I have been putting it off when hes pushed me in the corridor etc and now its time to act any ideas where I should aim taking into account my height and me being broader than he is? Thanks 10 POINTS FOR BEST ANSWER!