I agree w/ Dan! Ya gotta just do It. See It's like swimming, can't learn until ya get in the Pool!
But that doesn't mean you start on the hi dive either. Groove all your own stuff first. Keep the bits cool w/ water or oil like power steering fluid as Ron says. Don't overspeed 'em. It's OK to do a couple for freinds who will work with ya, But--again Dan's right. Ya have to consider bit life here.
Study all you can from all sources, training materials, this forum, and it doesn't hurt to find a Mentor in your area. An older mechanic, or a carb/tuneup specialist would be a good choice. You need to be a sponge for learning and info. See if you can find a mechanic Car Person buddy, someone to go back and forth with, so you aren't alone.
We are always here of course...
You've had some success, build and grow on that.
Get familiar with some aspect of Grooving, say: the PCV System, Ignition, IAC limiting/re-routing, just any part of all this. How the Groove works and why. What basic Principles apply to the Groove, can you explain to someone else WHY this works? Practice that, and try to keep it simple and direct. Practice on your wife or whoever. Ron's Training DVD and materials do an Excellent job of explaining the Groove, but try to get to where you can explain it in a short nutshell.
Get comfortable w/ knowing the Groove, them study another part of this. Repeat 'till you can explain all of it to anyone. Think of this: YOU are Training somebody brand new, they are Depending on your input.
We are giving an engine what it needs to run Cleaner, make more Power on Less Fuel.
Study,Think, and Get dirty!
Tracy G