Gene therapy holds great promise and has sparked great interest among researchers, healthcare providers, and patients alike because it offers the possibility of cures, particularly for rare diseases with a genetic basis. However, the field is in its nascent stages, and the ideal methods and solutions for unlocking the full potential of gene therapy are still being developed. The specifics of gene delivery, from finding a reliable means of introducing genetic material into target cells to reducing the risk of adverse events, can complicate the development process. In addition, it can be difficult to determine the appropriate approach to securing regulatory approval. In this white paper, we explore general principles to optimize the likelihood of preclinical and clinical trial development success, and provide a more specific focus on considerations for adeno-associated virus (AAV) based gene therapies. We describe regulatory guidelines and explain how pharmaceutical sponsors can ensure a scientifically valid gene therapy development plan.