Beyond the game, what's involved in an ideal session?
A meal. My gaming group gets together on average about twice a month. Those sessions typically last from 6:00 PM to about 10:30 or 11:00 PM, so not a long session by many people's standards. But every session has the first hour being a meal that we eat together. The meal is often a group effort, with different people bring various courses, desserts, and beverages. It has always been part of our routine, and a critical part because it allows us the chance to catch up with each other's lives, share stories, give out the birthday t-shirts (another tradition I can outline if people are interested).
Pragmatically, this social time probably helps people focus during the gaming session but more importantly it reinforces the fact that we believe that gaming, at its core, is a social event. This all starts to sound a little like "friendship is magic" but seriously it is the relationships that develop vis a vis the gaming table that really matter in the long run, now how your defeated the Yellow Orc King of the Amethyst Mountain or something.