If you have a good niche domain name, You need not follow any strategy to sell it. People who are in need will automatically contact you to buy the domain name. All you need to do is to make a clear contact details on whois database through which only people would get your contact information. Don't enable privacy protection as it may hide your private details. You can visit WhoisXY.Com and have a whois search on your domain name to ensure how your details display. Other than that you can also place your domain in domain name auction sites, place ad in local classifieds, Place ad in forums, etc., to sell your domain name.