Learn about the way stepper motors work, what that means when using them and what i think is important when adjusting their drivers!
http://www.youtube.com/watch?v=bItYRMLGoVc
Love your videos man. Was going to start up my own, and even started obtaining the cameras for it but as soon as you started doing yours I was just “Nope, this guy has some really nice videos! No way I’m going to be able to do anything that high quality”. 
Dito what @ThantiK said…I love the videos. I get a lot of my info from them that i pass on to others.
I’m not really getting anything new so much as I’m not sure I would be able to convey the information as nicely as Thomas does it.
Thank you @ThantiK (and @Mike_Smith )!