When fighting 1v1: Use the combo E,Q,W,R
This combo ensures that stun with Q, and a sure hit with that W. If they're not dead yet, then use your R if you don't think you can finish them off without it.

When fighting team fights or groups: Use the combo R,W,E,Q
This give's off amazing AoE(Area of Effect) damage. Its a great way to get the other team low health with just one person. If you have team mates beside you, you are almost guarenteed to win that fight.

To farm minions: Use combo W,E/ Q,E,W
Being Brand, you can farm insanely good. I usually farm just using W on a group of minions, and E on a minion in the middle of the group. But for maximum damage, you could Q a minion, E that minion, then W the whole group. Later in the game, its over kill to the poor things.