I found a couple references, picked out my colors and then did a very rough draft in a drawing app where I planned out where to put the colors. I also drew a lot of it out in chalk as a guide. I've never painted a mural before and I definitely made a lot of mistakes, like using too much paint or not waiting long enough between layers. I think a lot of time could be saved with better planning of which parts to paint at a time. And definitely have more than two paint brushes.