Odds of Hanging On
Making catering a fulfilling long-term career depends almost entirely on word-of-mouth. When people enjoy themselves at an event, they'll remember—and when they want to throw their own, they'll remember to call you.
This is why you print those business cards. There are thousands of caterers in the United States. You're competing for their business, so don't let them go anywhere else. The best compliment you can receive is a referral.
Although a tip would be nice too.