Another screen cap from the movie Singing in the Rain.
A few things I take into consideration.
Flow % (I'm trying to keep this at 100%) I'm trying to do this for the sole purpose of increasing my painting speed. Although, there are times where I go in with a softbrush and a low flow % to just nudge it into the desired value, I try to keep it at 100% throughout the whole project.
Working with colors and unfamiliar lighting.
Using images with cast shadows.