I recently attended the State of the Map conference (OSM's annual, global conference), and that inspired me to start improving the map around my area. I discovered a lot of small details I assumed would have already been mapped. There's a lot left to do, even in a fairly well-covered area of the world.
This helped me plan better for when I go out mapping—all of the apps are slightly wonky to use, so you have to develop your own custom flow to be efficient.
Out of curiosity, what type of feature are often left to improve?
I've been mapping my area as there was quite some drastic changes to my local park, but aside form that and the occasional post box I struggle to find meaningful edits.
You might know this already but the app (Android only I believe) StreetComplete (https://wiki.openstreetmap.org/wiki/StreetComplete) can be used as a low-effort way to fulfill minor improvement quests in your area.
If you are looking to contribute meaningful edits beyond your local area, the Humanitarian OpenStreetMap Tasking Manager always has things to do that can help folks working in areas affected by natural disasters: https://tasks.hotosm.org/contribute
In my area at least, I've found that even where the road networks are complete there are usually a lot of things that can be done to aid navigation. Some examples:
Walking: Tag roads for sidewalks, add footpaths and crosswalks.
Cycling: Tag roads for bike lanes, add bike paths.
Driving: Tag roads for turn lanes, and tag intersections for turn restrictions.
And of course POIs are always missing or need updating or additional info.
Out of curiosity, what type of feature are often left to improve?
I do a lot of geodata analysis where building footprints are important and there are a ton of buildings missing once you get outside the main city centers. Even just 15 minute drive into the suburbs from where I live and you go from every building mapped to less than 20% of buildings mapped.
I've added a couple of (non-clinical) buildings to my local hospital in London. I've also added some department locations. Tempted to say that counts as meaningful but the low-tech solution of good signage is, IMO, the best way to help people get around the place.
This helped me plan better for when I go out mapping—all of the apps are slightly wonky to use, so you have to develop your own custom flow to be efficient.