Grind out those professions
Fact: The more characters you have with maxed-out professional skill, the more markets you can take advantage of. Even if you're a more casual player, remember -- having access to an endgame professional cooldown (such as Transmute: Truegold) was worth thousands of gold in the early days of Cataclysm. It's easy money, and all you need to do to cash in is simply have as many toons as you can sitting at 525 professional skill and ready to go for MoP.
If you've got a few characters sitting at level 60, 70, or 80, it really is a great time to grind their professional skill to 525, even if you don't want to spend the time getting them to level 85. Cataclysm ore, herbs, and cloth remains relatively inexpensive. Plus, each and every month leading up to MoP offers you another chance to complete profession quests at the Darkmoon Faire and get a relatively painless five skill points. (They add up quickly.)
There's no worse time to level a profession than immediately after the start of a new expansion. No one ever makes money by playing catch-up. And with everyone else in the world trying to level professions to 600, you're going to run into some major competition for resources. Beat the rush. Grind to 525 now.
Profit off the gold-poor
If there's one thing we learned at the launch of Cataclysm, it's that anything used by endgame players will be expensive. The new-for-level-90 flasks? Expensive. New-for-level-90 gems? Expensive. A new-for-level-90 enchant? Potentially expensive.
But for every player out there spending 1,000 gold on a flask or 2,000 gold on a gem, there will be three or four players who simply don't have that kind of money. And there will also be players uninterested in spending top dollar to gem and enchant gear that they'll be throwing away for something better in weeks, if not days.
These players will be looking for bargains, and that's where you can come in. A number of Wrath-era enchants were strong sellers in the opening days of Cataclysm. Same goes for Wrath gems and even some Wrath-era flasks. They were all used during the grind to level 90 and even by some players while running endgame heroics and raids.
There's no doubt that some Cataclysm-era consumables will be in demand. And just as logically, there will be some that won't be in demand at all, depending on what the market gets flooded with as people push to 600 in their professions. Heck, some enchants are still cheaper than the mats that combine to make them.
Picking winners this far out is tough, but there's no reason to have to guess at this point. Don't make the end products ahead of time. Simply have a decent stock of raw materials on hand for when MoP launches. Spend your downtime the first few weeks crafting those materials into whatever offers you the highest return on your investment. Worst-case scenario? You'll hold on to the mats, let the Cataclysm glut clear out of the market, and then (eventually) sell the raw mats to levelers at a profit.
Bags, bags, bags
When Cataclysm launched, I made a killing off bags. For months, my main had accumulated obnoxious quantities of Frostweave Cloth and Infinite Dust without anything to make with it all. It was a fortuitous problem; instead of auctioning cloth for next to nothing or vendoring it, I started crafting bags. Hundreds upon hundreds of bags.
I ran through my entire stock of Frostweave pretty fast. Thankfully, though, I had no trouble finding more of it on the Auction House to craft more bags. By the time Cataclysm was ready to launch, my bank alt was full up with 20-slot Frostweave Bags.
Ultimately, each bag sold at a 1,000% to 3,000% premium over the materials cost. Demand remained strong long after all my competitors' bags sold out. I sold out even sooner than predicted and found myself scrambling to buy up as much Frostweave cloth as I could on the Auction House, chasing the price up to its current astronomical figure. My only regret was not making more bags ahead of time.
When Mists of Pandaria launch, there is going to be a similar -- if not greater -- need for bags to supply all those newly minted panda bear monks. It's hard to imagine you'll have a better use for all the Embersilk you gather between now and then, so just keep socking those bolts away.
Maximize your profits with advice from Gold Capped. Want to know the very best ways to earn 10,000 gold? Top gold making strategies for auctioneers? How about how to reach 1 million gold -- or how one player got there and then gave it all away? Fox and Basil are taking your questions at firstname.lastname@example.org and email@example.com.