One subject I really enjoy shooting using a macro lens is flora and fauna. This can include anything from vegetables (kale or asparagus in this case) to bugs (I only shoot dead ones on a window sill). Luckily (or not so luckily if you hate the cold) I live in an area that has no shortage of snow in the winter. So I played with the texture of snow on some green kale. The textures you can pick up using a macro lens are amazing. Another great place to find texture is by laying a subject (in this case asparagus) on a wood surface. I made sure to use a small enough aperture (f/8) to get a good area of the image in focus.
Here are a few tips and examples that have helped me. (Notice the flora and fauna images?)