I started to use this recipe some 2 or 3 orcs ago: on a beige ( bleached bone or similar) base i add a glaze of a yellowish brown (nazdreg yellow - contrast - in this case), then redo thin beige lines, reglaze, repeat at will to enrich the wood grain, add very light green spots/lines, then finish up with scorched brown or snakebite leather ( the contrast one - a jack of all trades to me) glazes all over, with some black on the edges. In case of things made up of more wooden parts I'd try to create variety using different beiges or greys for the grain and different browns/reds/greens as glazes