Everybody who joins my group is someone I already know outside gaming, or someone another member of the group knows outside of gaming. If you are invited to join us, someone in the group has already determined that they get along with you and you're probably a good fit for the group as a whole. I have had players come and go because they've decided they don't enjoy the game style or they're just not interested enough to prioritise gaming, but I've never lost anyone due to personality clashes or bad feelings. I've just never had time for that kind of drama in any aspect of my life, and gaming has proved no different.
Beyond that, I think a key factor is that I'm not looking for players who will read the rules, devour background material and are under pressure to constantly drive the session forward. I just need you to turn up, not be argumentative/disruptive and pay attention to the things that matter to your character. I make it extremely easy for players to participate and will happily teach through play. If you enjoy sitting around passively, I'll try and give you opportunities to get more involved, but I won't demand it. I've noticed that my newbie is gradually getting heavily involved more often (I assume just because he's gradually becoming more comfortable), while I have another long-term player who has always been fairly passive most of the time. For the latter, if he's happy turning up session after session for more than a decade, I assume he's content with that, and I'm not going to demand more active involvement.
Having a large group also enables us to have the games proceed even if people can't attend. I have some players who sometimes can't make it to quite a number of sessions in a row. That's just life, and I don't view it as a problem. There are people who would claim someone who doesn't attend a third of the time isn't really that interested, but if a player is making it to 2 out of 3 sessions over the course of a decade, I defy anyone to argue they're not genuinely interested.
Some players don't like the style of game I run or end up prioritising other things in their life, but I've had a group size of 5 - 8 players for over 25 years now and most of the current group has been with us for 15+ years.
In summary, my solution is:
- Don't recruit gamers, recruit people you already know you'll get along with.
- Make it easy for people to participate.
- Cultivate a relaxed, friendly atmosphere where mutual respect is the norm.
Edit: One other big advantage to the way I do thing is that I am completely unaffected by the mood and nature of the wider hobby or industry. It doesn't matter what's popular or in print or whether the corporations and influencers are attracting new people to the hobby or how the biggest gateway games are performing. I run the games I want to run and I'm happy to create my own gamers rather than going to a pool of gamers someone else made. D&D/WotC could collapse entirely tomorrow or become the most popular hobby in the world overnight, and neither event would have any meaningful impact on what happens at my table.