To prepare for the Redis Certified Developer exam, one must study the comprehensive study guide, which covers seven sections including general computer science knowledge, Redis keys, data structures, data modeling, debugging, performance and correctness, and working with Redis clusters. Hands-on experience with the Redis CLI and experimenting with different data structures and commands are also essential. Taking practice exams and identifying knowledge gaps will help maximize chances of passing, while Redis University courses can provide additional preparation and knowledge. With a thorough understanding of these topics and sufficient hands-on experience, individuals can prepare themselves for the certification exam and become a proficient Redis developer.