Once you've settled on an entertainment venue and signed a contract, make sure that they send or fax you a booking confirmation -- and then follow up again a week later, and then shortly before the event. You don't want human error to ruin your party.
Some entertainment venues can offer special packages to make your life easier. In many cases, they'll provide all the dishes, flatware, linen, tables, wait staff, food, and sometimes even the entertainment. Don't hesitate to ask about what they'll throw in for an extra fee.
Believe it or not, you can get some entertainment venues for free. For example, you can often book outdoor pavilions or gazebos at parks, if you book early enough. Of course, you'll still have to arrange for party rentals, food, and everything else.
