One way of recruiting new IDers is for current IDers to craft and upload images that are marked up with easily digestible ID tips (text, arrows, etc.). Here’s one I made for Calopteron terminale, a secondary upload for this observation. So if I make an ID for a Calopteron spp. and the observer is curious about why, I can quickly provide either a link to the image or even embed the image in a comment. I know of at least one person who then went on to use that information to correct misidentified species in the genus.
I don’t have data, but I think conveying ID tips visually can convert interested users into IDers at a higher rate than just providing ID tips by text. It takes a few minutes to create such graphics but I highly recommend them. I also like making them, in part, because the process teaches me about the organism. And, if it matters, I’m not a Calopteron expert. I just decided one day that it might be fun to learn how to ID them. I think iNaturalist is full of similar folks … people who are genuinely interested in improving their ID skills but don’t know where to start. It’s just hard to pick up ID skills with the current system (the “why” of an ID is rarely communicated).