There are two approaches I take when building a project. The first is working from preconceived designs such as sketches or photos and the second is creating freeform where I just wing it and let the project go where it needs to go.
Here are some examples of projects that were built from concept art. Some examples are well refined designs and some are very loose sketches representing the desired goal.
Boris The Bolter
Charles McScardeylantern designed by Jasper Anderson
Sir Rip D. Fleshkin designed by Breck Torres and Dustin Obermeyer