Some advice for auctioning.
At least until you start hitting higher levels, or particularly rare items, don't try selling at the suggested price. Instead put a starting price of about 50%-60% and a buyout price of about 70%-80%. Sure you may not be making the absolute maximum amount you could but you are much more likely to actually see a sale, particularly of lower level items. Experiment with the time you list items for, but I tend to go for 24 hours.
Also auctioning becomes
much more effective if you buy the minimal points from the store(the aprox $6 one). This permanently upgrades your account to premium status, which allows you to auction 20 items at once rather than the single item you can with a pure free account. You also get another 2 characters per server which will help with grinding the favour for store points later, along with a larger number of messages stored in your mailbox (50 instead of 10 I believe).
You can use the auction without this, but it probably wouldn't be worth it until you end up with really high value items.
If you do buy the points it's probably a good idea to hold onto them until you have enough points to purchase the packs that give about 100 or more favour, as you gain more points for each 100 favour your character acquires. Check here for the list of packs with how much favor each will give
http://ddowiki.com/page/Adventure_Packs