Wood is easy to do, and can look pretty neat with some work.
Then click on your colour blending mode and select 'colour'. It looks more like wood now. See the image below for how to change colour modes - its in your layer palette. What it does is basically gives the same effect as holding up a piece of brown cellophane, giving the colour tint to whatever is under it. If you want to be extra clever you can add a more realistic look to the wood.