What Determines Price?
There are many factors so it's difficult to nail down, but these are some general guidelines:

· Demand - How bad do players want or need it?

· Rarity of the item - Items that are more rare will typically sell for more. Be on the lookout for various items that are sought after by many professions, such as Heart of Fire, Wildvine, etc.

· Level of the item - Higher level items sell for more money

· Cost of sale to the vendor - If the vendor will pay a lot for the item, players will set the item price above the vendor cost.

· Auction house availability - If there are a lot of the items in the auction house, it may drive the price down.

· Trade items - If the item requires rare or expensive components, the item will typically be sold for more money.

· Level of the person who will be using the item (i.e., listing a level-10 item for 20 gold may not work as few level-10 players have 20 gold)
Buyout Price
Always have a buyout price. Many players want the items now and don't want to wait. Many players are willing to pay the higher buyout price just to get the item now. Try not to set a ridiculously high buyout price. This will cause buyers to say "what is that guy thinking?" and they might not even bid on your item based on that buyout price. Buyers are easily offended. It is better to not have a buyout price than to set one too high. The exception might be extremely powerful items such as purple items or items whose worth is completely unknown.

Timing
Timing can be very important for selling items. If the auction house already has a lot of the items you are trying to sell, you should wait until another time. You can also just lowball the current prices by setting your price below all of them. There are also good and bad times for auctions. A good time is when a lot of people are playing, such as during the evening or weekends. A bad time would be very late at night.

Enchanting
You can disenchant some items and then sell the resources to enchanters for a bigger profit in the auction house.

Create a Sales List
If you're selling profession items that you create, you can write a list of the ones that you will be selling. You can include what components are required to create those items as well. You should also include your current price list. This list will help you be more organized and let you spend less time selling your items. You'll need to continually update your list as you add new items for sale or remove items that do not sell. You'll also need to modify the prices as the market for those items changes. You may find spreadsheets are very useful for this purpose. You can also print them out easily.

When you sell an item, place a check on your list so you know to restock that item in your store.

Component Storage
Purchase the biggest bags you can for your bank slots. Buy as many extra bank slots as you are able to. Organize your bank with all of the profession components in their proper place. If you're a tailor, one bag can be for mageweave, one for runecloth, and another for thread, dye, and other special ingredients. If you keep everything organized, you can gather the components more quickly, create the items, and sell them in the auction house.