Carrier relationships are important for brokers to have unique market insights, capacity access, and establish long-term partnerships. The document provides tips for brokers to build carrier relationships through the onboarding process of collecting key information like contacts, preferred lanes, equipment, and services. It also recommends a three-stage phone call approach to connect about a load, update capacity information, and try to book additional loads to create ongoing value and strengthen the relationship over time. Building relationships takes effort but pays off with continued growth opportunities.