Ok anyway I did today a progress of a mattepaint, I can explain a bit how I did.
1. First I painted a rough sketch and put some basic color in it. I usually do this first to get a view and an idea of how the result would be in the end.
2.Now when I get an idea of the mood I start to search over some photos (digging up some photos from my library) and refix the light and shadow and color of photos. It is really important to fix the view and size of the photos to fit with the environment. Ok I added some dummies the details will be last now focus on the rough first.
3.Ok now for the details, I mixed with some buildings from 3dtotal and my own and did some paintover to them. Now for the details and details and details I added two layers that balance the mood of the whole paint. Now I am pretty happy with it, hope you learnt something:)