To become a Full Stack Developer, start by gaining proficiency in both front-end and back-end technologies. Learn HTML, CSS, and JavaScript for front-end development, and choose a back-end language like Python, Ruby, or Node.js. Familiarize yourself with databases (e.g., SQL, MongoDB) and frameworks (e.g., React, Angular). Build practical projects to gain experience, and consider completing a coding bootcamp or online course to consolidate your skills and knowledge.