If we're in an unfriendly area we take watches (with those with better vision at night taking the middle watch) while the DM rolls randomly for wandering monsters (or inserts a not-so-random encounter if they have something planned). If present, any elves have a four-hour meditation early on and either cover the sleep of others or keeps them company / explores the camp perimeter.
If we're in a fortress / trusted town we might ditch watches and just get a good night's rest.