This is a very exclusive area to be in.
The very few brokers I know often have 1000's of domains, to manage, not worrying whether they sell or not.
Some make solid money, selling for 4 figures or more per week, but this is an exclusive club, there's not many like this.
Domain validation is very subjective, a bogus domain name that is the right fit for the buyer can often outperform domains with attractive keywords, that you would believe have a much better search and clarity value.