Elements to a successful eBay listing:
1 - Great pictures. eBay will actually be requiring all listings to have pictures. Make sure yours is attractive
2 - A keyword stuffed listing title. Most people do not understand this. The vast majority of eBay users find things through the search bar and NOT browsing categories. So your listing title has to have searchable terms.
3 - Your headline as the first thing in your listing body. This is the proper place for the headline that you actually want your reader to read. Obviously, it should provoke some interest. If you don't know anything about copywriting, download some books on the subject. They will change your life.
4 - The body of your listing should relay benefits to the reader (again, copywriting). If you want to get super advanced, embed a video or something to add something different.
5 - Pricing. If you are doing an auction, then start it low. High starting bids are killers. If you are doing Buy-It-Now, price reasonably. People look on eBay for deals. You should know your price points from your market research before you listed your item.
6 - Support. Be responsive to your prospects and customers. These are people who are considering giving you money!
Follow those steps and you'll be alright. If you are selling lots of stuff, then you can think about building a back end.