Things are really picking up in terms of selling vendor items and in terms of buying and selling trade goods on the AH itself. Many of the items that I'm trading now are volatile enough to buy and sell for at least a 100% profit on each trade. I'm finding that this is the absolute best way to make money in the AH, pick a few items, buy them up when their cheap and sell them when their not.
Of course the trick is figuring out which items are volatile enough and figuring out what is cheap and what is not cheap. Going to sites like WoWHead is great if your just looking for ideas, but generally you should already know the items your trading. These are items that are in demand and are regularly needed by craters and people leveling their professions.
As for figuring out what is cheap and what is not cheap, you just have to watch these items, there isn't really any other way.
Final gold tally for today is...196g 77s 73c