Don't make your shadows too dark on bright days.
It's tempting because the contrast out there is so intense and cameras can struggle to capture the full dynamic range. But remember always that your shadows are lit by the blue sky and reflected light.
Concept art by Harley Jessup for Ratatouille (2007), dir. Brad Bird, Pixar Animation Studios
Layouts for these pieces were done by Jessup, Enrico Casarosa and Jason Katz