A couple tricks I use to increase my DPS when tanking raid bosses:
Make macros for each of your main moves (Shield Slam, Devestate...) and add Heroic Strike at the end of each so it will always be queued up. You will not want to use these macros during trash or heroic dungeon runs as they may rage starve you.
Also adding Shield Block to the start of your Shield Slam macro helps, unless of course you need this regularly for mitigation.
Hope it helps
Addon Author: What's Next? - AllPlates - Sudoku - Death Clock - Super Loot