As a developer evangelist, gauging success is often subjective and requires tracking various metrics such as awareness, engagement, and API adoption to determine the impact of one's efforts. However, establishing clear goals and identifying signs of burnout can help make the role more sustainable. A full-time gig may be necessary for excellence, but part-time work with strategic projects and self-care can also be effective. To become a developer evangelist, it's essential to understand why you want to pursue this career path and gain diverse technical knowledge, find a developer product you love, and develop the skills of empathy, patience, and hustle.