One of the things that Ty taught in his writing class was story maps. Basically, (in the form he was teaching us) they’re a simple device for planning a basic comic script. Obviously, story maps aren’t unique to comic writing, but Ty’s technique for using them is pretty specific to mainstream comics publishing.
Here’s an example of a story map that he filled out — I’ve seen this particular example used to provide a visual aid for his Writing Comics course. He also hands out blank versions in his class — I scanned one and redrew it in Illustrator because I like doing stuff electronically.