finds himself in the Workbench with several 15mm scale Russian WWII fighters...
I let the decals dry thoroughly, and then I apply another coat of Future. This provides a protective coating, and helps reduce any noticeable edges between the decals and the mini.
When the Future is dry, I apply a coat of matte finish. Then I apply pastel dust to simulate soot, exhaust, and dirt.
Once the pastel dust is in place, I apply a couple of thin coats of matte finish to seal everything and give a uniform finish. Sometimes, I'll pick out some areas with silver paint to give the impression of chipped paint, but otherwise the minis (once dry) are done...