The best way to be organized for power leveling is having a paladin or warrior friend that is willing to give you some time to take IMVU Credit on huge mobs of enemies that's in the instance.
Go to the Southern ramp before going to the Black Temple if you are looking for Scryer rep items. You’ll know you’re there when you see lots of Black Elves lined up waiting to be killed.
These mobs have a decent respawn rate as well. You’re only downside would be going back to the bottom of the hill once you’ve killed every single one of them.
Aldor and Scryers can still make some profit. Check your Auction House to see if there are competitions in this market. If you are lucky you can have the monopoly for these in your server so you can be rich in a short time.
These are easy kills and in just an hour you can loot around 1 stack of Fel Hide, two to three Fel Armaments, 30 to 40 Marks of Sargeras, and a couple of greens which can be sold for lots of WOW gold. Mana-casters though show be aware of the mana-burn these mobs are capable of doing.