Lets Be Real, Tracing Has a Bad Reputation
Everybody thinks you cheat at drawing if you do any type of tracing. Tracing has its purpose. Comic book sketches are what I enjoy doing the most and doing variations with transferring the image makes it easy to do with out a computer.
How you should not use tracing
Dont trace other peoples artwork and claim it as your own. That is rule number one and really the only thing you should never do. Artists that do collages take other artists work and claim it as theirs by altering it just slightly.
How you should use tracing
Look at the sketch of Wolverine above. I ran out of space on the right and used the tracing paper to finish up the sketch. Using the tracing paper I transferred it to watercolor paper by taking a dark soft graphite pencil then pressing it down on the watercolor paper. It works magic and so much fun to do!