I have found that the steps below are the most efficient way to farm dungeons:
1) Take off all gear (Make a Naked set to speed this up)
2) Enter Instance
3) Queue for BG
4) Macro 1 & Reboot WoW
5) Die
6) Run to Boss
7) Relog
8) Equip Gear
9) Kill & Loot Boss
10) Take off all gear
11) Die again
12) Enter Instance
13) Leave Instance
14) Reset Instance
15) Rinse and Repeat
Steps 12 and 13 are mandatory. If you Enter Instance and Reset without leaving, the next time you do steps 1-5 you will not be a ghost on top of your body. You will be ported out of the dungeon and be at the graveyard, which messes up the entire process and creates wasted time.