As you approach more people for cross-promotions, word will spread, and savvy business owners will start to approach you to make deals. As you build a cadre of satisfied customers, you'll earn a reputation as an honest, hardworking small business owner who's easily approachable. Here's a list of other ways to attract promotional partners:
Grow your business. People like to work with growing businesses. The more clients you get, the more you'll attract partners.
Generate buzz. The more people hear good things about you and your business, the more they'll want to be associated with you.
Promote your unique concept. The more interesting your concept and the more differentiated it is from other catering operations, the more people will want to work with you.
Be easy to work with. The easier you are to work with, the more partners you'll have. Listen carefully, compromise, and honor your deadlines. Deliver top quality services, and people will line up to be your partner.
Whenever you're approached by a potential partner, listen to what the person has to say. Give her five minutes, because you'd want her to do the same for you. If you're not sure about what she's offering, ask her to send you a summary of her proposal. If she's serious, you'll receive a followup within a week. If she's a bit shady, she won't put the details down in writing and you won't hear from her again.