Always double-check any HTML before posting your auction. Whenever possible, always use a photo - it always increases the interest in an auction. If you haven't got a digital camera or scanner, have a look around the internet to see if you can find a suitable image to use. For example, if you're selling a voodoo graphics card, have a look at the voodoo website to see if they have any suitable pictures you could use. PC prices are very volatile and PC buyers are notoriously price-conscious, so it is always worth comparing what you are selling with other online retailers to confirm that you are not charging too much.
Reserve price Have a look around the site before posting an auction.
See what other items are selling for, and use similar pricing. If you set your reserve price too high, your item won't sell, so your reserve price should always be the lowest possible amount you'd accept for your item. In many cases it is very useful to have the same starting price and reserve price. The bidder can then make an informed decision on whether or not to bid - knowing that if their bid is the highest they can win the auction. If your starting price is below the reserve price, a potential bidder may bid on the chance they'll get a bargain and that their bid may be the one to meet reserve.