Near the action but not in the path of it. The corner of a dance floor works well; a hallway does not, because a queue there blocks the room.
Give it about 8 by 8 feet, and keep it within roughly 15 feet of an outlet or bring an extension cord.
Avoid putting it directly under a very bright downlight — the booth brings its own light, and a hard overhead adds shadow under people's eyes.
Didn't solve it? Text (914) 825-5498. If it's your event night, lead with that — those go to the front of the queue.