Glaze

Most people forget about glaze, but it is very important. Evercoat (who makes the Rage line) makes a great glaze.

Glaze can be applied to the whole surface, or used in spots. Glaze is actually recommended over over a "spot putty". Why? Because it does not shrink. Spot putty will shrink differently than the filler it is on and can cause the paint to get blotchy. But because the glaze is made from most of the same materials as the filler it shrinks with the filler and everything keeps its finish for a long time.