As people have said your basic rotation won't change, the biggest piece of advice I can give is to practice weaving in your off GDC's during your berserk window if you can. The Fell Cleaves should be your priority but if you have 20 to burn and berserk is wearing off then I would suggest you get in that onslaught charge. When you hit 64(?) you can work on weaving in upheaval. I recommend using thrill of battle just before upheaval since it scales with your health. Once you hit 70 you'll want to try to weave in more ogcd's between your fell cleaves.