An eBay business plan focuses primarily upon the golden principle of selling items in an auction-style environment: market need. A seller puts up an item that s/he thinks will attract a buyer; in this instance, obscurity doesn't really matter. People often look for the weirdest item that has sentimental value to them. Another important component to an eBay business plan is creative thinking. After all, eBay itself operates on such a principle. It took the auction idea and fit it to the online world, and the result was surprising in how it captured the attention of the worldwide marketplace. A business plan that relies on selling items at an online auction therefore needs to understand the seller's target market.
A seller's business plan also relies heavily on personal initiative. Since overhead is generally quite low, sellers can begin with a high gross margin. eBay's fee structure would obviously factor into all revenue forecasts in your business plan, but a seller can stand to make a fairly comfortable living—so long as they are selling items that people want.
A seller must therefore completely understand his or her target market. If the market enjoys comic books, it's a safe bet that they will like memorabilia from their favorite character's movie, television show, or video game. If they enjoy hand-made clothing, they may be interested in an antique loom or sewing machine. If they enjoy antique weaponry, the product selection is virtually limitless. And so on.
Your business plan must also be completely adaptable to the market's needs. If interest dries up for a certain line of products, always make sure you have a back-up. In this way, selling items at an online auction such as eBay is similar to crop rotation. Civilizations that relied on one single cash crop ended up dying out; ensure that your business' survival doesn't fall into the same fate. Diversify, plan, adapt, and watch your market like a hawk. These qualities will ensure the success of your eBay business.