I feel for you. Nobody likes to have their items not sell. I've been there, as have countless others. So don't give up.
The things that have kept me out of the red have been doing solid research on what I have to sell or want to sell. This has helped me determine whether an item is good to sell, what kind of profit to expect to make, how to structure my auction title, what to put in my description, etc. Most people use eBay's completed auction search to do their research, but I use a paid service. eBay's search is the best way to start.
Now, I don't if you are selling your own stuff or are buying and then selling. A lot of what I've sold has been stuff I bought. If you are selling or want to sell purchased items, be prepared to walk away from anything that won't give you the profit you are looking for. I often say that you make your money when you buy something, and I have found this to be true.
If your selling your own stuff then you will probably have more flexibility in the selling price, but you should still do good research. I spent hours teaching my mother how to do this and she has been successfully selling a variety of stuff (both her own stuff and purchased items) for almost a year now.
This is just me rambling...
HTH,
Clint