Originally Posted by
figuratively
Switch to Blooddrinker over Heartbreaker. If you can boost your haste while ditching mastery without sacrificing (too much) item level, see if that's an option. (Yes, a lot of our tier gear is poorly itemized, yes it feels bad, man.)
Marrowrend at 6 stacks of Bone Shield. Avoid capping your RP. Sounds like you got the basics.
You'll have to keep an eye on your surroundings, with respect to where you have to be for specific mechanics and how to position mobs that don't require the melee to stand in bad things to keep attacking, or to run all over needlessly moving mobs. (That said, mob pathing can be stupid, and they'll move regardless.) Coordinate with your partner tank to know which role you're taking, and/or when taunt swaps are appropriate. (DBM will often warn you, but on things like Krosus for example, you don't need to wait until the other tank has 5 stacks, just until yours fall off.)