Rankings are based on the following ability priority:

1) Hunter's Mark is applied to target before encounter
2) Serpent Sting is maintained
3) Chimera Shot to refresh Serpent Sting only
4) Rapid Fire
5) Readiness
6) Steady Shot X 2 to maintain Improved Steady Shot Buff only
7) Kill Shot when boss is under 20%
8) Aimed Shot only when Master Marksman procs
9) Steady Shot

Stat Importance

Agility > Hit (to 8%) > Crit > Haste > Mastery

Reforging

1) Reforge your weakest stats until you've reached 8% chance to hit
2) Reforge to Crit from Haste and Mastery