One of the biggest challenges a coach faces is how to convey skills that he or she cannot adequately demonstrate.
This is a more common issue than you might think; there are many coaches teaching above their abilities for many different reasons-- they've lost skills you had years ago (in particular jumps and spins); they've developed a roster of students that has passed the level they were at; new skills have been introduced since they stopped training, for instance, the quad jump; or old skills that predate their own training have been reintroduced. Right now we have a generation of coaches who never took figures now having to teach the loop figure for the new Moves tests.
So what should coaches do?
Don't teach above your teaching competence.
And remember that competence at teaching is not the same as competence at skating. (Many coaches skate better than they teach. I teach better than I skate.) How do you know your competence? Be a PSA rated coach. Don't try to vet your own coaching level; you're bound to get it wrong. Imperfect as it is the PSA ratings system requires that you have teaching competence at specified levels based upon national standards. Parents need to ask their private lesson coaches what their PSA rating is. If your skater is working on double jumps and your coach is not working on PSA ratings, think twice. I cannot tell you the number of coaches that consider PSA ratings and/or continuing education "bullsh*t." If parents insisted on only hiring rated coaches, we'd see fewer injuries and attrition among recreational skaters, because the teaching would be better.
Don't demonstrate a skill that you are not absolutely confident that you are doing correctly. This does not only go for low-level skaters like me. I see a lot of funky demonstrating from high level skaters. Remember that some students are very visual learners, and can copy your mistake perfectly. If you see a skater whom you know works visually making a new mistake after you demonstrate, have another coach observe your demonstration and be prepared to accept an honest assessment. This doesn't mean you can't teach that skill. It only means you can't demonstrate that skill. If you can't do it, don't.
Demonstrate pieces of the skill
I can't jump an axel, but I know how to do a step through and I know what the print should look like (the mark that the skate blade leaves on the ice). In fact because I can't jump an axel, I set about learning the pieces-- if a demonstration is not available, coaches have to have other tools at their disposal. If you can't do the whole skill, demonstrate the parts that you can. Chances are these isolated pieces are what is going wrong anyway. No skill falls apart all at once.
Know what you're looking at
Skills progress in sequence, from simple beginner skills like crossovers which start with strong edges and good alignment over the skating side, to complex advanced skills like triple jumps, which start with strong edges and, uh, good alignment over the skating side. Hmmm. Right. There are common errors, and most skills go wrong very early in the set up. Coaches should know these common errors and how to correct them.
Have a demonstrator
Every program has junior coaches with excellent, current skills. All of the younger coaches love showing off for the kids, and the kids love it too. Use your high freestyle skaters to demonstrate; just make sure that the skater is demonstrating the skill you want in the way you want it done.
As with everything in teaching, a good coach needs not only to use all the resources available, but also to understand when which resources are appropriate.
The day after I wrote this I had an adult skater ask me to show him how to do alternating three turns down a continuous axis. So I showed him-- badly! This is something that I can do rather well, but there I was botching it! I regrouped and executed it properly, but it forced me to really think about what I was doing, and to make sure that I had everything lined up-- brain, skating skills, body and blade. We had a good conversation about it, and I just thanked my lucky stars that it was an adult with a good attitude and not a kid with a parent watching!
Lesson learned-- Practice what I preach!