Please make sure there are accomodations for people with disabilities and have the courtesy to give them spaces close to amenities -- bathrooms, dining hall, sessions, etc. Don't expect them to use upper bunks (Yes, this has happened).

Provide as many different session spaces as you can, so that the trad singers can have one, the accompanied singers can have one, the tune players can have one.

If you notice that some singers are not capable of jumping in in the approximately three seconds of silence before someone else does, please ask them to sing. On the other hand, discourage large sessions that go around a circle -- nothing kills good singing faster than a huge session with too many rules.