We had a few constraints based on table location: Person notorious to get drunk was out of sight of the bar. Person with medical problem close to the toilets.

We had a few constraints based on table location: Person notorious to get drunk was out of sight of the bar. Person with medical problem close to the toilets. Young nephew prone to pick candy from jar was diagonally seated to a candy jar, because the whole family loves to see al the strange ploys he came up with to 'randomly' pass the jar and take a candy. Yes we love him :-) We also seated groups according to preferred language as a secondary constraint, so we had Dutch/French/German/English corners of the room.