Start by selling things you have no use for anymore. Once you get the feel of selling items try buying a few things. You'll have an even greater understanding of how things work on ebay. Then find a certain product you're interested in and have experience with. It will be much easier to sell something you know about rather than a foreign item. Next find a wholesaler that will sell to you in bulk for cheap, just use google and type the product you want to sell + wholesale and find a reliable source. Then put your stock up on ebay and wait for your buyers to roll in.