Evolution of a Mural 
I have my own way of working as do all artists, but mine is really a little different...
I do not sketch anything in pencil before I start.  I have my sketchbook sketch I place next to me, to refer to, but I never draw on the wall.
I do all mural placement using painter's tape.  I then do everything using my paintbrush without sketching.  My brush shows me the way...
Clients are always facinated watching me so I thought I'd put my system on our webpage.
All my work is done freehand, never traced.  I am old school!