Want to ruin your model? Apply the wash all over it and try to wipe off the excess.
Dilute your paint about 90% thinner. Take a fine pinted brush and apply a small amout at the intersection of panel lines and watch capilary actio pull the paint along. Do the same at the base of raised details such as bolth heads and hingess and where two plates meet. You can lay larger amounts in engraved grill work. What you'll see is the effect of heightened shadows. Sturgeaon's right about the colors, but to keep it simple, dark brown and black will do. It's best to ues oils or enamels rather than acrylics.