First things first: 250K gold mark has been hit yesterday "and I'm not even trying" (ie: I'm not aggressively investing my time in the AH and trying to acquire big-money items, and I am still "wasting my time and money" on helping out my guild with achievements).
Once I'll have all my toons to 85 and all the Cataclysm quests done, I'll be aiming for that 500K mark.
Secondly, some smart people have noticed the new pet achievement in the upcoming patch and have started to slowly buy them before prices start raising.
Unfortunately, people like me have already been raising prices and suddenly they are all selling.
So I got rid of 3 Argent Tournament pets for nearly 1K gold each (they were on a long slow slope near 600g since the beginning of the expansion).
Xmas pets are very much in demand and my experiment to raise the prices of those is slowly starting to pay off as the 100g pets are now edging closer to 300g now (so many people have been stockpiling those, so they are throwing them up on the AH because now they are seeing a good profit margin appearing, thanks to me).
Thirdly, I have 300g worth of proof that selling enchanting mats for 1-300 leveling during the weekends is a good business that I'll keep working on.
I notice once in a while that a new contender enters the market with a big stockpile of items, like a very specific type of dusts and essences.
I usually don't interfere with the type of items he's trying to sell and pick up all the rest of the areas he's not covering.
I know that we are supposed to keep an eye on the Books of Glyph Mastery to flip them but I haven't seen a single one for weeks.
Either the supply is nonexistent or the demand is extremely high.
May consider investigating on how to farm those.
Also, a friend and me might pick up on Faid's advice concerning her experiment with the Potion of Treasure Finding.
We both are in need of a lot of cloth to finish leveling our tailor alts and want to get all our Dreamcloth cooldowns (except the one that requires Chaos Orbs) running to make some 26-slotters.
I'll even be picking up MobInfo2 again and endure its memory-hungry hell to try to compare stats with Faid's. (The things I have to do for gold, some days...)