1. Listings - You can either list your item on "Sell > Start Selling Now" (this is on the right top of your eBay summary page after logging in to your eBay account", or you can download turbo lister (PC) or Garagesale (Mac) and edit your listings there (this is always more efficient).
2. Pricing - It depends on your business planning / strategy. You have to start positioning yourself online, to decide if your focus is going to be price or convenience.
3. Communications - Stay efficient communications with your customers is the key to the success of your business. Since customers are not able to see your product or visit your store physically, it becomes more important if you can provide precise and detailed spec of your products and assist customers with any queries they have efficiently.
4. Reputation - Your reputation is built based on the feedback you receive from your customers. A few elements will be factored into the scores you get: Item as described, Communication, Postage time and Postage and handling charges.
Keep this in mind: The Customer is God!!