There are a few basic iNaturalist rules/guidelines and features that new users generally don’t know and have to find out on their own. As a result, the same mistakes are consistently made by (it feels like) every new user. Not knowing to mark things as cultivated is a big one, and I think not knowing that it’s possible to add multiple photos to a single observation (resulting in duplicates) is also significant. Just the other day someone with over 400 observations asked me how to put multiple photos in an observation.
I think simple tutorial that every new user (mobile or desktop) needs to go through would significantly reduce this. This has been suggested many times, but @tiwane has also indicated that there are plans for that, so I’m not sure if an actual feature request would be useful?
I don’t know if the onboarding has changed at all in the past year, so my assumption is that it’s no more than what was described here. I’m guessing that most users try to figure a program out on their own first, and only look for guidance if they get stuck. So if they are successfully able to post observations without any indication that something’s been done wrong, then they may just continue to do so.