Recently, I jumped into creating Revit families. Unfortunately, throughout my use of the program thus far, creating families was this "do I really want to go there" kind of issue. I've never seen a family created live in a demonstration. Sensing complexity, I avoided creating them completely.
Finally, I dug into them and what I found was amazingly easy. So I thought I would help people get started, and I created my own online course in creating Revit families.
With the urging of my friend at TurboSquid, I've made this available on their site. Go to the Revit Market on their site and search for "Roger Cusson" and you should find it easily.