Using the characters you have optimally, and getting more characters if necessary is an important part of optimizing your goldmaking operation. So let’s take a look at what you can utilize them for in TBC.
Cooldown based recipes have always been a staple of goldmaking alts. Something that you can login once a day to generate some gold is perfect for this kind of setup. In TBC there are two professions with relevant daily cooldowns, alchemy for transmutes and tailoring for the various special cloths. I already covered the basics for alchemy here. The TL:DR is pretty much to do the earthstorm diamond on alchemists below 70, and skyfire diamonds if you can get that recipe.
For tailoring the prices are generally such that you need to have the correct specialization to make the cooldown worth it. Just check which of the cloths is the most expensive one and pick that specialization, you will want to park that alt close to the designated crafting spot. This can be done on level 60, as you can get the specializations at level 60 as long as you have the right skill level in tailoring.
Shuffles can also be great for goldmaking, and do not necesasarily require you to be level 70. Classic materials are still highly in demand as players need to level through the 1-300 range to get their professions maxed and get the TBC benefits. Enchanting is one of the better professions, so many players pick it, guaranteeing demand for classic enchanting materials.
My favorite shuffle
The white bandit mask shuffle was the first goldmaking method I ever learned, back in the original TBC. You craft White Bandit masks, which cost 5 mageweave cloth, and disenchant them. As long as the price of vision dust is more than 2 times the price of Mageweave cloth this will be profitable, and that is usually case. Vision dust is the biggest bottleneck for leveling enchanting and sells absolutely fantastically. So with 215 tailoring and 150 enchanting, you are ready to rumble, which means you need to just have an alt at level 20 to get the required profession skill. This does not take long to set up, so get going.
Low level crafting
There are some interesting crafts that are still relevant. The Wrath of Cenarius ring from the Silithus quests for cenarion battlegear is very strong for AoE farming. This means that paladins that play will want to do a good amount of logistics quests. This means that the cheaper turn ins for logistics quests in particular, will sell quite well. All of the potential quests can be relevant, just make sure that you do not overprice the items. If you have any of these crafts or have any of the relevant professions, then keep a few on the AH. You can easily look up the list of items used on the list of quests over here.