Selling domains is not easy and takes time. You can always list your domains on this site's auction or fixed price pages, but you should expect a small amount if successful at all.
There are steps that must be done: 1) Make sure your domains appear in domain registrars, by listing them on a service like afternic 2) make sure they all have a sale landing page, you can use epik or dan for that. important - always have a buy now price and not just an "offer" option, because domain names displayed with a price have a 50% higher chance of selling. 3) if you have time at hand and want to sell them fast, do "outbound" marketing - contact people/businesses/companies that might be interested in your domain and offer it to them. Goodluck