Making the most of adult traffic – what to do

I have 4 adult tube sites

site 1 gets 1500-3000 uniques per day
site 2 gets 1200-3200 uniques per day
site 3 gets 1000 – 1500 uniques per day
site 4 gets 1000-1500 uniques per day

im using tubecorporate popunder and juicy ads on the sites but only making a few cents per day.

Does anyone have any advice on taking this to dollars per day instead of cents?