Chris, the real trick is indeed "washes" and "drybrushing". You can see here on my Marder III this first picture was after a light colored wash to just fade the paint a bit and give it a dirty apperence.
Then I applied a dark pinpoint wash to the details on the model and this is the result of the dark wash.
(sorry i didn't have 2 of the same angle but you can see how the dark wash surrounds the details and creates "shadow" around them and makes them start to stand out.)
My next step will be to drybrush a lighter than original color of each color of the camo that will highlight the raised parts even more, make them look faded, and I'll also add some "scratches" and "rust" after that. Now don't take what I tell you as gospel as this is my first armor kit I've built (since I started painting models anyway
) and I'm working off lots of articles I've read and mostly the advice of Moses, Shermanfreak, and others on the forum who are offering suggestions and help on my techniques. I'll offer any advice I can and so will the others. This is a great bunch of guys and gals who are very helpful and quite talented.
Eric