I've made one before. Typically I would do something along the lines of scripting out your actual spoken dialogue before trying the "draw" portion.
Once you've made your script on all the topics you want to cover, start drawing. I would recommend getting a whiteboard and marker, hanging it on the wall and drawing there as you point a camera+tripod at the white board.
Once you're done drawing for your video, take the footage, do your commentary, speed-up or slow down your video as you need to in order to keep up with your commentary, and you should be good.
Anything else you do to your footage is your choice