Essentially, if you have a domain that a well qualified domain expert would be willing to market chances are pretty good that the domain(s) are already marketing themselves. You just need to answer the domain inquiries.
If you want an acid test of the quality of your domain(s) see if one of the major players is willing to list them for live auction at a future domain traffic event or a domain auction at a major industry event. If you can't meet the "live auction" test chances are you won't find a broker of any level of connections and competence.