To become a successful full-stack developer, one should start by mastering both front-end and back-end technologies. This includes languages such as HTML, CSS, JavaScript for the front end, and languages like Python, Java, or Node.js for the back end. Understanding databases and server management is crucial. Additionally, familiarity with frameworks like React, Angular, or Vue.js for the front end, and frameworks like Django, Flask, or Express.js for the back end, is essential. Continuous learning, staying updated with new technologies, and building a strong portfolio of projects are also key to success in this field.