Have a quiet room
Have a space to take a break away from the bustle of the conference.
Networking and socialising is an important part of conferences, but it tires a lot of people out. Have a clearly-marked, designated space where people can sit quietly, not talk to anybody, and recover some of their energy. I wrote about the quiet room at PyCon UK in 2016, and sitting in the quiet room is how I’ve got through a number of other conferences.