GREAT 3D instructional design principles:
affordances
open layout
customizeable
interactive
consistent
... many principles that parallel good website design
Torley's guid to making movies - many tips 'n' tricks over the years I've distilled for your convenience. Whether it's video tutorials or story-driven machinima, the basic principles are the same. I know your time is short and you want to get started soon - this guide isn't meant to be all-comprehensive, but is intended to smooth your path so you can get up and running quickly.