If you want to earn serious money from eBay, you need to have a well-thought out business model. Selling on ebay is getting tougher -- just look at the number of auctions that closes without a bid. Go to the boards on ebay and you will hear even oldtimers complaining about how stiffer competition plus higher fees make it so much harder to sell on ebay.
The key success factor is: Sell products that people actually want.
One success model of ebay is the couple Jay and Marie Senese (username jayandmarie) of the 1-cent CD fame. They have the highest positive feedback number of all sellers on eBay. Their business model is to buy very low cost CDs in bulk (those that CD stores sell in their discount bins) and offer them on ebay at a starting price of 1 cent http://www.businessweek.com/magazine/content/04_23/b3886080.htm Their success is based on the fact that they stumbled on a sustainable business model with products that people really want.
eBay has several ways for you to determine exactly what the hot items to sell on their marketplace:
Items In Demand = the most popular items currently within that particular category. To see the In Demand page, go to http://pages.ebay.com/sellercentral/sellbycategory.html
Hot Items by Category Report = a monthly report that lists the fastest growing categories on eBay for the previous month. Go to http://pages.ebay.com/sellercentral/whatshot.html and select "Hot Items by Category" from the menu on the left.
eBay Pulse = "a daily snapshot of current trends, hot picks, and cool stuff on eBay". Go to http://pulse.ebay.com/ to see eBay Pulse in action.
Merchandising Calendar = eBay promotes specific categories on its home page each month. Savvy eBayers know that this home page exposure results in more interest in such categories. Go to http://pages.ebay.com/sellercentral/calendar.html to view the current Merchandising Calendar.