Before you can give any referrals, you have to know what a good customer will be for your business contacts. Tell them what you're doing and that you need them to help you know what to look for.
Don't let them tell you "anyone with a business" or "anyone who breathes!" You know what they're doing? They're concerned about losing potential customers, so they open the door as wide as possible.
But in sales "a confused mind says no." Too many options? You won't remember any of them. A vague description isn't going to help you in your busy day narrow down the field.
The more descriptive and specific you can get them to be about their ideal referral, the easier it will be for you to find one.
Ask them what kind of problems their clients have. What phrases they use when they are looking for the kind of help your friend can provide. Have them tell you how they found their best customers.
Help them help you help them!