I have two techniques which are a bit more primitive. The first is I paint a medium to light brown base coat to start. Once it dries, I use a thin dark brown Sharpie to draw in some lines and knots. From up close it looks ok, but from farther away it looks pretty good.
The second technique, for smaller surfaces, is to paint the area with a silver Sharpie. Once it dries, I use a dark brown Sharpie and basically color in the area. It gives a nice wood grain look.
Here's a pic of my second technique on my '75 Int'l Scout II dash: