Practice. Film everything, make random edits. This lets you get familiar with the cameras, software, and your own mental processes. When you watch others' videos, pay close attention to the angles, lighting, movement, etc. I'm not a film maker by any means, but the other summer when Level 1 released all their movies, I felt like I learned so much about moviemaking just from watching Josh, Freedle, and others progress in their own skills and techniques.