At first I would just promote anyone/anything relevant to the niches I like/build freesites in.
Like Licker4U mentioned, I'm starting to take a good look at the tours and see if they appeal to me as a lover of the niche. If they do, then I'll promote them.
I've also used recommendations from this forum on several occasions. Plus Greenguy's stats and the GG&J resources pages, and a few people's sigs.
But I really do have to think a tour for a particular site is appealing enough.
