To make painting easier, I generally leave the arms off if, when installed, they overlap the body and make it difficult to paint the details underneath. Both the arms on this figure would have made it difficult to reach and paint areas to the standard of the rest so they are added later.
First up, this figure has been primed with Humbrol 28 light grey which is a nice neutral light colour. I always prime my figures before painting in acrylics, be it in Humbrol enamel or with an auto paint rattle can. I can however recommend the new Vallejo airbrush primer as an alternative. When the primer coat is fully dry, the smock base coated with a 2:1 mixture of Vallejo 885 Pastel Green and 924 Russian Uniform ww2. Several light coats are required, thinned with distilled water, rather than one thick coat.
Next step is to outline all of the seams with 872 Chocolate brown. This is quite important. Firstly, it shows you where the seams are, and thus where the breaks in the camo pattern should be. Secondly, by it's very nature, camouflage does just that, it hides detail. You will be surprised how hard it is to pick out details once the camo colours are in place.
This step defines the actual splinter pattern with the chosen colour, in this case 826 German Camo Medium Brown. This need to be sufficiently thinned to outline the shapes, but retain that sharpness, especially on the edges. I think of it as very similar to Chinese brush painting, I try and define the pattern using single overlapping strokes.
I do not try and follow the pattern exactly, what I am trying to do is capture the essence of the pattern by using the shapes I see and replicating them. Also bear in mind the proportions of the colours, you don't want the main colour to dominate too much. There is a lot of "base" colour showing in this pattern.
Remember too to break the pattern at a seam or pocket flap. This part would have been cut from another piece of cloth. It also adds a bit more visual interest if the pattern does not match at the joints.
Next step is to just fill in the gaps. Again, the paint needs to be thinned considerably otherwise you will get a nasty build-up of paint obscuring detail. You will see from the photo that I have finished the brown pattern on left hand side of the smock (as worn), but the right side has only had one coat. This will give you some idea of the paint consistency. It can take up to four coats to get a nice smooth covering. (Left side had three).
Next photo shows the brown pattern completed on the smock.