Well I made a speedie "how to paint wood texture without custom brushes walkthrough". I am a little bit uhm, (insert funny word here) because of people tell me "OMG I need your custom brushes!" You don´t need them really. You can do good texturing already with standard brushes.
This was a quickie, I _could_ have spent more time on it, this piece of wood texture took me actually 10 minutes.
No magic involved, not even a reference used. But that was how I basically did the wood panels [link]