Old barns and buildings are fun to get into the detail because they are so full of textures and linear shapes. Various pencils, pen and ink, watercolor washes - are some of the the tools of texture to get your fix.
I did this sketch primarily with watercolor pencils. Then I used a very small and pointy watercolor brush sideways (after dabbing the excess water off first) and lightly dragged it across the pencil in one direction, with the grain of the wood. The pointy tip can get into the tiny dark cracks for detail. Later, I went back in with watercolor washes to add more variety of color and contrast.
I drew this free-hand without tracing. Working on my accuracy! (That is, my accuracy of asymmetry!)
