I started contributing to OSM recently after a bike trail was built near me. The arial imagery typically takes years to refresh around here so I walked it a few times to capture GPX tracks and then drew the new path. It was exciting to see my contribution percolate out to various apps that depend on OSM, and meanwhile Google and Apple have both ignored my edit suggestions and deny the path exists.

So I have a fairly fresh newcomer's perspective and here's what I suggest to get started: keep it simple and start local. As others have noted, skip the complex mapping app and go straight to the website for feature edits, or download a simple mobile app like Every Door and focus on businesses and landmarks near you. Go on a walk around your neighborhood and look for old/incorrect/missing businesses. There may be errors near you about places you actually care about, and it is really gratifying to fix those.

There were restaurants near me that were missing, shops that had changed hands, etc., that were easy fixes but years overdue. I captured some basics (names, posted hours, the phone number posted on the door, etc.) with Every Door, and then later logged into the main OSM website and fine-tuned the entries. I got into a pattern of fixing one or two entries every evening when I went out for a walk and pretty soon my walking route was all up-to-date. Then I started paying attention to things like stop signs and cross walks and found a whole new kind of little, incremental edits that nobody else was doing.

It's been fun, I've made useful contributions, and my laptop is still Java free.