I usually use a light acrylic such as Tamiya Deck Tan as a base coat, then overpaint with burnt sienna oil paint.Brush it on with a stiff, coarse bristled brush to get the grain effect
The oil paint takes a week or so to dry, but it's much easier to manipulate into a nice wood grain finish.
This article goes into great detail on painting wood grain.
Stefan that ship looks really wonderful. What kit is it?