My latest WoW char is a lvl 16 Warlock, and she has almost 30 Gold, and I’ve not really been to AH a lot yet, since I created her only 3 days ago (and only play late at night).
But these are some of the tips, I use for her and my other chars:
Use Auctioneer
This goes without saying, of course. With this plugin I can see at once, if I should vendor an item or put it to sale at AH. I also get the market price, the “no competition” price etc. This is perhaps the most valuable plugin, I use. If you download the program Curse Client, you can easily search for an install Auctioneer.
Put Things for Sale on Week-Ends
It’s my impression that most people shop in AH on Fridays to Sundays. On my main realm, I’m noticed that a few put things for sale Thursday evening/Friday, and the price keeps climbing until it peaks on Saturdays, and then fall slightly on Sundays.
Duration of the auctions
Since people will probably be buying in the weekends, no need to use a listing above 24 hours, unless it’s objects without auction fees. I put a lot of my objects up for sale for only 12 hours, since I figure the price will climb after that time, and then I want to sell a new load of objects. If I undercut the buyout price for a reason, I never go above 12 hours. I never undercut dusts and shards prices, and since these are sold without beforehand fees, I put them up for 48 hours.
Always use buyout
This one is a killer option! Always, always use a buyout. People are NOT patient. They want their new armour now, not tomorrow. If they have to wait to see, if they can win the auction or not, they will probably prefer to buy another item, perhaps even at a higher price.
Undercutting minimum bids
Instead of undercutting the buyout price, which will cost you money, try to undercut the minimum bid, if there are a lot who sell the same item, you do.
When people sort their search results based on lowest price, this is not determined by the buyout price, but by the minimum bid. But be careful! Don’t go below the price you can sell the item for to a vendor.