A few years ago a colleague of mine who is the Director of Marketing at a midwest CPA firm shared a great marketing and business development idea with me. In order to expand new business opportunities, his firm asked their existing clients for introductions to the clients' vendors and some of their customers as well. Since they were all in the same industry, it helped build the firm's presence in the niche and enabled them to develop some hot leads very quickly, as there was a strong connection between the prospect and their (very loyal) existing client.
This seems all too simple, but how many of you have actually asked a client, not just for a vague "referral," but for a real introduction to a key vendor or customer? Your clients will probably be thrilled to do this for you and it is a much easier reuqest to fulfill because they have names at their fingertips, rather than trying to come up with a business acquaintance they might recommend. It is a targeted, specific request and one that you can benefit from making!