No matter what you want, chances are you’ll be able to find it on eBay. You’ll also probably find it for the lowest price too. However, just because 
eBay makes it easy to buy, doesn’t mean it makes it easy to sell—at least not if you’re trying to earn serious profits. For that, you’ll want to try out the following tips.
Let’s start with the main focus of your listing: the actual product. Presentation is everything on eBay and can often be the difference between celebrating a sale and lamenting a loss. Don’t just take a lot of pictures; take a lot of really good pictures. Consider investing $100 in equipment that will provide a white background and ideal lighting. This extra touch will give your images a professional appearance. No one wants to see what your carpet looks like or squint to make out areas covered in shadow.
If you have an eBay shop up and running (and you really should), you can start taking advantage of your extra inventory through upselling. The easiest method with an eBay shop is to offer your customers discounts on shipping if they add another item to their cart. Consider making the arrangement that the more they add, the more you take off.
Now let’s talk more about an eBay shop. Yes, it will cost you at least $20 a month. However, on average, those with eBay shops sell 25% more than those without them. So that $20 investment could be negligible within your first week.
Keep in mind an eBay store by itself is not enough. You need to optimize it. A great way to do this is by having a logo made for your business and outfitting the store with it. There are a number of other options for giving it a unique look. Nowadays, freelance designers can make you a logo for less than it costs to run the store for a month too.
Selling to a customer is great. Upselling them is even better. Upselling them and then emailing or messaging them later when you’re running a sale or have more items that match their interests is the best. Finding new customers is a lot of work, but keeping old ones is easy and lucrative.
Admittedly, the tips above either cost money, will take time or both. However, those are really your only options for turning big profits on eBay. The competition is stiff, but the above tips will give you plenty of firepower.
Source:
http://www.ebay.com/gds/18-WAYS-TO-BOOST-EBAY-SALES-and-EBAY-PROFITS-/10000000004060596/g.html