I've only sold 2 items on eBay and I'm getting ready to sell another item. (I must be a pack rat who keeps a lot of junk.)
I learned that a good picture is the best "tool" to sell your product. I used white bath towels as a simple backdrop to photography my items against. I took about a dozen photos and selected the one that looked the best (no flash glare, no shadows, etc.)
I also looked for similar items that were on sale (or were sold) so that I could find out how I should describe my items (and how much money I could make). Use the AIDA principle in your description: Attention, Interest, Desire, and Action. Two powerful words are FREE and NOW (if you have the opportunity to use them): FREE shipping, FREE gift with order, Buy 3 and Get One FREE, Don't wait: bid NOW, etc.
If you know how to use HTML in the description, use the color red (especially in the headline) because it is attention getting and invokes action.
Lastly, as a bidder on eBay, I like "Buy It Now" auctions to avoid the bidding process, although the final price is usually higher. I once got into a bidding war that went right down to the last second and I lost. What a bummer. On a dutch auction that I desperately wanted to win several items, I got up at 4 a.m. to make sure I didn't get outbid.
Good luck and get started NOW!