Anticipate questions

The more information you provide in your description, the less time you'll spend answering emails from potential bidders. So, if you're listing a necklace, include its length measurement. Potential bidders may simply turn to another seller because they don't have the time or patience to email you, if you do not provide enough information.

It is easy to overlook basic information if you know your product really well. There is an assumption that bidders will understand what you mean, and vital information gets left out.

To overcome this :

List all the items of information a potential buyer will need in order to make a decision. Size, colour, new or used, composition, etc etc. Have a look at a few ads, go into the stores and see what extra information they have included on their site. When you are happy with this basic list, use it for every ad you write.

You could also have an interested friend go over your ad, and pretend thay are a buyer.
The trick with this is to look at your ad from the buyer’s point of view, and give them what they need. This will cut down on the questions you get, and help you make money selling on eBay.