I drew this quick sketch of Wolverine over my Christmas break. By quick, I mean like a good hour drawing this versus drawing for a couple of hours.
Notice how my sketch lines do not line up perfectly with my thicker drawn lines (especially Wolverine's hands). This happens all the time when I draw. I sketch out something and midway through inking the sketch I realize that I don't like the placement of a body part, or that the proportions were off, or that I found a way to draw it better. This is the case for every artist with almost every drawing they do.
Wolverine is drawn initially with a G2 gel pen, then traced over with a Papermate Flair pen. The shadow lines and cross hatching is done with a .03 and .01 cm pen.