Great question. the good news is you don't have to figure this all out yourself... Just like you dont have to code your own site. Right? (I hope not?)
You're needing a clear value prop and positioning... as well as a market matrix of competitors... just to start!
THEN the real work begins. The case study video at the bottom of this page shows you from start to finish the process in a few minutes:
http://bit.ly/1pWjNRF
But I don't recommend you do this yourself.
Hire the right people for the right jobs and your headaches will vanish immediately!
The problem is that videographers DONT know strategy... and strategists DONT execute or make videos.... So the link above will show you how those two worlds combine seamlessly together.