I am interested in how easy it was to sell the name, how you promoted the name, etc. Some domain name brokers accept multiple listing of domain names i.e. you can post the same domain name with several brokers. Current information about domain name brokers can be found here . Post your sales notice with as many brokers as you can. The increased coverage can only prove beneficial.
Quantity is important.
This is not so relevant if you can only afford one or two domain names. If you are thinking of buying a number of domain names, try and build up a small portfolio of names. Instead try and be as diverse as possible. Assuming that person A and person B are equally adept at choosing domain names, then person B has 19 times as many chances to sell a name as person A. Person A can make a tidy profit by selling the one domain name. However, person B is guaranteed to make back the outlay all 19 names with the very first sale.