With this particular point, you’d have to identify everything that makes up the grammar point because if you try to brute-force memorize the hiragana, it’s going to make for a long journey. So we’d be able to break it up into the following の・が・上手 (じょうず) - the latter meaning “skillful”.
For grammar points that involve vocab words, I suppose you could add it to your SRS of choice like Bunpro, Anki, etc. For the other grammar sections, the new in-house write-ups should break down each part of what’s getting used. Before the write-ups, there was basically just the structure breaking things apart to show you what’s going on, but the team here did a good job at trying to explain everything so people wouldn’t have to memorize it all too much. There’s going to be some points where you’re confused about the make-up of everything; in that case, I would first recommend checking the community thread relating to the point (which can be found on the grammar page under ‘Ask a question’) and then if you’re still lost, just post a message there and someone for sure will answer your question.
Hope that helps!