OK, long post on how I did it!
First, Where is your traffic coming from, what country. Are you still thinking in English. What about German, French, Russian etc. If you have traffic from other countries, go to Babelfish, the Altavista free translator and get your keywords translated. More revelant content.
Check out archive.org, search the net to try and find out what the people are looking for. Just give it to them. Sounds easy, NOT!
Changing the master keyword all the time is not wise. The system needs time to optimize, however, make the master count. Thus do your homework.
Even if you get very few hits a month, FINDING HIGH PAYING KEYWORDS IS NOT SOMETHING IMPORTANT, IT IS ....EVERYTHING...
I played around and found a keyword for adult traffic that is paying me a consistent .90 cents a click. 25 people a day click on that. Did that help my numbers!!!!!!!!!. Find high paying keywords, also, remember, if you have international traffic, keywords pay different amounts in different markets. Maybe in the US it is cheap, but in the UK pays very well. That is where the real value of the related links are. The stats are updated real time so you can play changing the words around during the day to monitor ctr and how much they pay in that market.
When I started this journey, all my related links were automatically generated and paying poorly. Now I have put the related links in myself and my ctr is around 90% average and my per click went from .07 to now .21 per click.
Track your daily clicks on excel, knows what is paying well and what is not, change the related links and you can do this too.
http://www.iotaweb.org/ this site is where I found my high dollar keywords, also, the more hits you get, it SEEMS that Sedopro then pays more. I have no idea how they do it. but over .90 cents a click is pretty good. for my sick porn traffic. I have started putting in related links keywords that bend toward the sick dudes looking for extreme stuff. Won't mention names, but the click throughs are 100% in many cases and per click over .25 to .35 I guess sick pays.
Moral of the story, something I have heard many times, TEST TEST TEST, otherwise you are leaving money on the table.
Good Luck,