I simply did my research, asked coaches, watched test sessions, hung around with judges and evaluators on test days, and talked to my skaters; they are in continuous contact with their coaches, they get to interact with the judges, and I also asked knowledgeable parents, and I know far more than I used to. However, as I'm not a skater, there's only "so much" that I can learn - for example, I don't skate a bracket, so, I'm not intimately aware the way that a skater has to be on the way the edges work, etc. The parents who are ex or current skaters are so far beyond anything that I could ever expect to know ...
Judges and evaluators are required to have a minimum skating background in Canada before they can begin the progression; and then they have to do clinics, work under supervision, write exams, and pass evaluated standards. There is no way in the world that I could ever be at their level. So, I rely on my coach, and now that they are older, on my skaters.
I can interpret, for example, comments that say "wide stepping" on a mohawk, scratchy edges, underrotated jumps, etc etc etc, but, I can't "call" them myself. So, I can understand the feedback, but, I would never expect to be able to "judge or evaluate" the element. Except for a sit spin. I can call those things like nobody's business !!!!
I've seen more than a few clubs get in judges for seminars. It can be useful if the judge is articulate; you also sort of/kind of should divide parents into "entry level" or "advanced" as the quesitons tend to be very different.