If you keep some names since long time and they do or do not bring big revenue, here is a simple way to raise it using time. You should develop them, not anything difficult but something like 4-5 pages. Create or find a free template you will use for all your website, find one with an image in the header so you can change it to fit the domain name. Name the different pages with names that are related to you domain name, for example if your domain keyword is flight, create a sub page called cheap flights. With time google will catch them and they will bring targeted traffic.
For the content try to write something unique, os google will pick it up better as well.
It is very good for names you will keep years, after few months, they will get good traffic from google, and more and more as time goes, only increasing you domain revenue and its value.