After that, it's just good nutrition, sleep, and good skin care.
Now, things like botox, thread lifts, and fillers for the face/mouth are a another angle on this, but I would say that looking at many of the celebrities linked above, my husband (who is 40) looks younger than some of those folks, and I definitely do. We could probably give Joseph Gordon Levitt a run for his money anyway. And that's without all this fancy stuff (my husband and I anyway. we dont' have this fancy stuff -- which may be genes).
Anyway, I know that it's not affordable for a lot of people -- but it's not "you have to be a millionaire! in order to afford it" expensive.