Hosting well means noticing who’s standing alone by the snacks and walking over.

Being a good host is mostly a job of noticing rather than arranging. Any gathering produces someone stranded on the edge of it, and the distance between standing there and being included is one person walking over. That is a small act with a completely different weight depending on which side of it you are on. People remember who came over for years.

At the next thing you are part of, scan once for whoever is on their own and go talk to them. You do not need a good line. Ask them something, then bring one other person in so you are not their only anchor.