Take a comprehensive marriage education course, and refreshers every few years to keep communication clear, happy and enlivened. Ideally, do this early in the relationship to help avoid some of marriage's natural bumps in the road.
My husband and I enjoy teaching several formats of PAIRS workshops in Northern Virginia. PAIRS is an experiential class for couples to learn how to create and sustain a happy, passionate, long-lasting marriage. I've been teaching PAIRS for 17 years, and love how it open potentials for a thriving relationship.