Force Charge > Deadly Saber > Battering Assault > Rupture > Ravage.... is a pretty basic one but yea check Noxxic for all your needs i think Rotations etc are under the FAQ's section.
After rupture I go for annihilate to get it rolling, after that I might go with ravage.
Remember that annihilate has high chance to finish cooldown for rupture, so you can hit that back again soon as the current rupture ends on target. Soon as deadly saber comes off cooldown activate it, and make sure your ready to hit annihilate soon as it comes from cooldown to keep it rolling.
EDIT: Hehee...forgot that your not lvl 40-50 yet