one thing I have been succesfull with is flipping blue weapons in the past couple of days.

What do I do:

I check the AH for weapons needing a level 81-85 that are rare.

The Obsidium craftet level 81 weapons like and can often be snatched for 500g-700g - and easily resold at 1999g.
The one handed counterparts of those I have been successfull selling for 999g - so snatch them if they are less then 500g.

In addition all zone drop weapons are selling pretty good - from 600-1000g without a problem. The earlier players can take those the better they sell.

Up to now only one weapon returned to me, that I put up at something like 2040g and then tried again at 1999 and it sold (from 700 snatch price).

Weapons you should not take are those dropping in dungeons - they are not that rare and there is constant supply but not much demand.

However - I believe in about 2 weeks prices for Obsidium will fall - so don't try the crafted weapons for too long, as their supply will eventually increase.