This document provides examples of a "warm letter" campaign that can generate referrals for a business. It recommends sending a series of 4 personalized letters over several months that: 1) Inform contacts about the business, 2) Explain what clients can expect, 3) Provide a case study example, and 4) Share a client testimonial. Consistency is key - committing to send a letter every month maximizes exposure and results. Planning content for multiple months saves time. This low-effort campaign can drive ongoing referrals through regular contact with one's network.