The trick is to break a bone or two on the bully's body. Let him remember it for a few weeks.
And, if they are bigger, hit them on the back of the head as they go down the steps.
Did that in Jr. High to a bully who probably had about 100lbs on me. Repeatedly nailed him when he was down, too.
We both got suspended, and we just studiously avoided each other for 6 more years -— me, because he would kick my ass in a fair fight -— him, because he knew I would kill him in his sleep.