@tsrberry @joepie91 @baldur the answer to that heavily depends on what kind of project it is, who the users are, and what scale it operates at. if it's a small CLI tool developed by one or two people and used by a handful of linux sysadmins you probably aren't running into many UX design pitfalls. having really good docs is nice, having error messages provide context and guidance helps, being welcoming towards contributors and not needling them with endless style changes is very helpful.
@tsrberry @joepie91 @baldur if you're operating at a larger scale (especially on gui tools) then running annual community feedback campaigns is a huge winner. make it a simple survey form - minimum friction, maximum response rate. people will tell you all the things that have been bugging them but never got around to opening an issue for. commonalities in responses will help you direct your efforts and make a lot of users happy with relatively low effort.