I have sold many items on ebay and have discovered a few things. I consistantly sell with a high profit level, and very rarely take a loss on an item. This is the first of a series of articles that I intend to write on the subject, and this one will focus on the listing itself.

1. Always include an avatar picture. Most buyers won't even stop to inspect an item if they can't see a picture of it during their search. It is worth every penny, and adds at least 50% to the final value.
2. Use bold on items that tend to blend in with similar items. Anything you can do to differentiate your listing from the other similar items can do wonders. Expect about a 15% increase.
3. Use a good picture inside of your listing. A bright background, and a controlled flash make for a great choice. I found that a red background works great, and does about a 10% increase on the average.
4. Clearly and honestly list your item. Answer questions about your item quickly and honestly. I won't even bid on an item from a seller with less than 98% positive feedback.
5. List your shipping price, and be fair. I won't bid if a seller won't disclose their policies up front.
6. Check your spelling, and use every available space in the listing title. Hit on all available keywords without spamming.
7. Be careful when selecting the category. Think about who you are trying to sell to, and where they might look for it. You wouldn't look for a computer under a furniture category.

I hope this helps! Check back with me, I will be outlining some other ideas in the future!