Fellow illustrator and friend Marc Scheff created this great infographic titled "There Are No Shortcuts." It beautifully illustrates that in order to make great art, you need to do lots and lots of art making. Not just the big beautiful crazy works you dream of, but also lots of studies, practice, doodles, and sketches, and as much of it from life as possible. Every good artist I know continues to do these sorts of things long past the point of being called professional. In fact most artists would agree, you never stop learning, and so there is no reason to ever stop doing these sorts of things.
Marc has called this infographic "part 1", so check out his blog for the sure to follow up "part 2" and beyond :) Marc's original post with this graphic