BoatBuilderCentral.com has been posting a handful of how-to videos on YouTube. These both deal with the proper methods and things to look for in mixing epoxy. Simple stuff, but if you’re starting out you have to learn somewhere. (Note that there is no audio with these videos)
Epoxy Basics mixing a small batch
Mixing Woodflour and Epoxy Glue
Other videos can be found by searching YouTube for boatbuildercentral. Right now these include "Sanding High Build Epoxy Primer" and "Roll and Tip Painting".