I have a slightly different view on the matter than Woody:
I also make a good part of my money on the AH (I'd say around 50%). As I already do this for quite some time,
here are some experiences that may help you:
1. Always try to get at least the price for the crafting mats out of your sale. Remember that there is still a 5% listing
fee for the sale that should be included in your price.
2. There are very few armor or weapon objects that will be bought this way. If you don't want to be ripped off, don't
sell it. Make sure there is demand for what you sell, even before you craft it. If there isn't, leave it. From all the stuff
you can craft, 80% won't sell. The thing is to find out what are the 20% that will sell. That takes a lot of research at
the AH before. Take that time before you get active.
3. Don't take stuff people tell you about prices up 1:1. Always ask more than 1 person and evaluate a good middle after.
4. If you see that there is alot of supply to 1 product, although the price is right, be careful. Better wait with yours to
list, until the supply is moderate again, as you can expect others to soon list it for less. If that happens, better retrieve
your objects and lose what you paid for the listing than getting engaged in a price battle to the bottom, that would
then leave you with far more loss than a retrieval.
5. Finally always watch out for a good investment! Example: If Heavy Cloth is averaged priced 2500, watch out for the
2000 offer and invest in that raw mat, to have a price advantage later, after others threw their products like silk or
strap in, crafted and priced with the 2500 HC. Therefore it is better to keep a big enough money reserve at hand
than imediately stick it into a crafting project that would leave you emptyhanded when seeing some good investment
opportunity at the AH
Hope that helped a bit!