Make a file. When you first start planning for the big day, you're going to be swamped with information from caterers, bands, DJs, photographers, decorators, etc. To keep things organized, get a collapsible file with manila folders the various aspects of the affair. Save this file. It comes in handy if you will be planning subsequent parties in the future. This way you won't have to start from scratch when planning your next affair.
Are they open? Your first question to the respective members of your party staff should be about the availability of your date. There's no reason to get excited about someone that's already booked.
Bigger doesn't necessarily mean better. Just because the people across the street had an elaborate, glitzy, expensive affair, doesn't mean you have to as well, unless that's what you want. You can set yourself a budget, work within your means, and still have an outstanding affair. Don't succumb to people pushing you into extras that you know you cannot afford. Most good bands, DJs, caterers, etc. should be willing to work with you and offer you a variety of options at various price levels.
Listen to your kids. Your kids are the greatest source of information on what's new and hot on the Bar/Bat Mitzvah circuit. Let them share in the responsibilities of planning their special day. Have them accompany you when you meet with photographers, bands/DJs, caterers, etc. Let them write their own candle lighting ceremony or speech to give at the affair. Have them help with the invitation list. They'll feel more appreciative of your hard work if they experience some of the work for themselves.
Don't be afraid to be creative. At age 13, kids are usually very self-conscious about how they dress, what they look like, and how they act. Of course you want to make your child's day special, but you may feel apprehensive about doing some aspect of the affair differently in fear that your guests will not respond favorably. Consult your child on your ideas and who knows, you may set a new trend or two.
Leave extra space on the invitation list. When you've finished including all the relatives, friends, and kids for your affair, you might want to think about leaving extra openings on your list and ordering extra invitations. You never know when you or your child will be invited unexpectedly to another affair in which it would only be right to reciprocate the gesture.
Know what you owe. One of the worst things that can happen is to have a disagreement with a member of your party staff on the day of your affair about due payments. Carry with you the contracts for your entertainment, photographer, videographer, caterer, etc. You can also alleviate headaches by writing checks out the night before.
Arrange some quiet time. On the day before your party, spend some quiet time by yourself or with your family to keep you from getting too unnerved. Also, on the days following the affair, you may find the need for some down time to bring you back to reality. Treat yourself to a day off - you deserve it!
Don't forget your P's and Q's. While your party staff has had a pleasure serving you in the planning and carrying out of your affair, it's always nice for them to receive a special thank you by way of a letter or phone call following your affair. If you felt the service was outstanding, tipping is appropriate.
Relax and enjoy the affair. Mazel Tov! You have survived planning a Bar or Bat Mitzvah. You owe it to yourself to take this time to enjoy and savor all the hard work you've put into making this day a special one for your son or daughter. After the affair, look forward to the many phone calls you'll receive about how your affair was absolutely fabulous. Thanks to your dedication, you have created special memories that will last forever.