Sould i try to link with keywords already coming to my site, try to develop more (adwords tool), or expand from my list (adwords tool)? If i use existing search terms, am I working from the strength of the site? If I try something new, will I dilute the site?
yep use google tools they will give you what is ranking and run with is work pages and google will tell you whats they are giving you and keep working that