To achieve results like those in the second photo, I would use MM olive drab and dark green, Testor's green, and Tamiya yellow green. Starting with a base coat of olive drab, dry brush the raised areas with yellow green. Paint the shaded areas with a 1:10 mixture of olive drab and green. The deepest recesses should be painted with a 1:1:10 mixture of olive drab to dark green to green. Don't try to be exact in your mixture or application of paint. If you are, it becomes too monochromatic and unrealistic.
For items that would be painted, you can add chipping using light browns and tans. Any will do. I prefer Tamiya dark yellow(have a quart of latex that I had color-matched for $3), Testors brown, and brown water-colors(the cheap thrift store ones). Using a small, round brush(00), trace small lines around corners. If using a light brown, you can then give it a wash using the brown water color. If the item is metal, use a dark grey and trace hard edges. You may also touch your brush to the paint build up on the rim of the bottle, dab it against a rag and dry brush the piece with. The more you apply, the more worn the stowage looks.
Of course, this is all just MHO.