Keep Straight Shot up 100% of the time, during your opener pop two buffs before using a GCD and repeat until you run out of buffs.

My personal opener:
Quelling + Raging
Straight shot
Hawk Eye+Blood for Blood
Windbite
Internal Release + Barrage.
Venombite
Flame Arrow

Your dots are affected by buffs as well so you want those on before you apply the dot, after that just spam weave heavy shot and bloodletter. Another good tip is after windbite and venombite you can do 5 or more gcd's before having to refresh (depending on skill speed)