If it's a thumb TGP only you will have a hell of a time getting it ranked very high for any good terms. Seems only thumb sites that have been around a long time get good listings for good keywords.
However text is much easier to get listings with, as that's what the SE's are after. For thumb sites add good top lists with keyword rich descriptions and instead of using fancy graphics for each gallery section use text descriptions.
Something like "The best MILF galleries from the past week" or what ever.. For a thumb site, that's one of the only places you have to get your keywords in. Take advantage of it instead of putting a fancy graphic there, use text. Also get some Big text under your header graphics.
You can also always add "alt image" tags but from my experience that will only help with images.google, images.yahoo and so on, but not the real thing. It's still better than nothing but not the same quality traffic.
Also for a new site don't worry so much about the top keywords try to get more obscure stuff. Like you probably wouldn't get "MILF" but maybe you could get Hot Free MILF Galleries" then maybe later you would get "MILF Galleries" and so on. If you target your other site text right, you could eventually start picking up listings like "MILF Videos" or "MILF Porn" and so on.
I use
http://inventory.overture.com/d/sear...ry/suggestion/ to pick out keywords for what ever niche I'm working on.