I sketch my thumbs with a pencil and draw the final pages with a pencil as well. Whenever I start tracing a sketch I lose most of its essence. When I draw directly there's more fluidity and spontaneity. More mistakes, too, but those can be erased.
Also, some mistakes are pretty interesting to look at. My art made a huge leap forward after killing off most of my die-hard perfectionism. Highly recommended. <3
After drawing, I scan the pages. The paper I work with has a slight sepia tone which gives each page a nice tint instead of cold black-and-white. All my coloring is done in PhotoShop, with a trusty tablet.
For many pages I use photographs for textures and even as entire pages. There's lots of interesting textures all around you that can be captures easily. Especially good when you're waiting for a bus or friend anyway and need to kill the time!