First--remove all parts from sprues but where it makes sense to do so, leave a bit of sprue on there. The shocks for instance. We need some easy way to clip them to "ponzi sticks" for painting. And of course, remove all flash, debris, cross-tweeze, mold lines (every part has one) and so on. I have really gotten into good clean up. It satisfies my OCD to clean up all the grime, burrs, and dookie. Glue together what you can before painting. So far, easy right?
I know from experience that if I'm going to glue anything painted together and have it stick you have to scrape the paint away first. I hate spending a ton of time endlessly scraping paint so I have started to use more of Microscales' "Micro Mask" first. Brush some on, let it dry before you paint, and trim away what you don't want with an exacto knife. Then when it's time to scrape, just scrape a bit of the mask and (hopefully!) the whole mask comes off and you're back to bare plastic. BTW MM thins out with acrylic thinner and cleans up with water. Good stuff, but it can be hard to remove from deep crevices. So I don't use it everywhere but for chassis joints I used it pretty liberally.
Now it's time to "Ponzi stick" the parts. I took a bunch of wooden skewers for making shish-kabob and superglued alligator clips to one end. I clip the part (a bit I don't want painted, or can touch up later, see why you leave the sprue sometimes?) and then shove the sharp end into some styrofoam.
I paint in the back yard and then let it dry as you see here. The tools are to keep the wind from blowing the whole thing over which would really suck. What I really don't want to do is stink up my house so it'll stay outside for a while.
Now here's the trickiest thing of all. The frame assembly needs 2 or 3 coats, so I put on a thin coat and walk away. This is NOT easy to do!! But if I tried to cover this in one coat it will run and look crappy. Again, I will let it all dry outside to not stink up the house. Global warming at work!