Here are some great videos of preproduction work for Pixar’s short film Presto. I found these videos through the character design blog.
This first video is a collection of various gag ideas. I didn’t realize this is how ideas are pitched. They even add sound effects to sell it.
Here is the animatic. Look at how well worked out all the timing is.
Writer and filmmaker Vince Di Meglio edited together this instructive selection of clips from Buster Keaton films to show how he used symmetrical composition. In his description, he writes:
After watching twenty-nine Buster Keaton films, I was struck by his use of symmetry and center framing. This is an attempt to capture that. Before Stanley Kubrick and Wes Anderson made it famous for modern audiences, there was Buster Keaton.