Speak with Uzzek at Far Watch Post in the Barrens.
The Horde honors its warriors because their strength is unquestioned. But the truly great warriors are great students as well.
Seek out Uzzek. He is a veteran of many battles and now instructs young warriors in the ways of combat. You will find him south of Far Watch Post, the orc garrison on the border of the Barrens and Durotar.
Hello, young one. Here for some instruction, are you?