Some topics you can study that are related to product design include how to perform user research and communication-centered topics like writing and how to give presentations. You could also study tools like Adobe Illustrator, InVision, or Treejack. You could study computer-aided drafting (CAD) programs or gender analytics. You could also study topics that are tied to the type of product you hope to develop, such as fashion if you want to design clothing or website development software if you want to build websites.