It's important to find a niche on eBay

When you are deciding what you want to sell on eBay think about your interests and hobbies.  What do you know the most about?  What types of products would you be comfortable selling?  This may seem odd as you might think that as long as something sells what difference does it make if you actually like the product?  The point is that if you know and understand a product then you understand its value and are therefore better able to describe it and understand what price you should ask for.

When you list your item on eBay you have to provide a description along with one or more pictures.  The description will either excite your prospective buyer or will turn them away.  If you are really into your product and love it then buyers will flock to you because they feel your positive energy when you describe the product.  If you aren't interested in your product then that lack of interest will also show in your description.

So find a product or group of products you are interested in.  Make sure that there is a market for them on eBay and then create your own niche and start selling those types of products.  You can even open an eBay store and list several similar products that you can suggest to buyers after they have bought one of your products in an auction.