i just started painting mine. Use spray paint. Use Krylon grey or white primer. After it primed spray it with the color you want as the base gray, green, earth, etc. Then add the finishing touches the cockpit, nose, tail colors, etc. The spray paint gives you a nice even coat. Go light and fast over the piece about 6 inches away . if you go slow you’ll put on to much paint. no good you lose detail. If you really want a sharp looking piece add decals.
look at some of my pieces on combat miniatures face book site.