Thank you, oh kind people!
FF, you are welcome to ask questions, my methods are not secrets.
Wood - I airbrush the base colour, a mix of Mid Stone (Pactra) and Beige Brown (Vallejo) depending on the final shade - darker or brighter. Then I paint with a thin brush a pattern using a darker mix. Sometimes I retouch with brigther again. Then follow thin layers of Clear Orange. I usually use Pactra but I have just ran out of it and in this model I used Tamiya. The number of layers depends on the depth of orange you wish to get. Finally I apply dark brown wash which also serves to add some more wood pattern, not just to emphasize the surface detail.
The leather is from the bas mix of Red Leather and Chocolate Brown (both Vallejo) with dark brown wash retouched numerous times to get the satisfactory result.
In both cases I use a water colour wash which has to be sealed with clear (gloss, satin or matt - or a combination to get the desired level of gloss/matt).
There is really nothing more to it. Although some testing on scrap plastic pieces is advisable.
