When optimising a product, income stream or process, you need to make sure you are designing for the users. Build target audience(s) based on what you know and create new or revised audience personas using existing data and knowledge. This will help you identify gaps in your knowledge and with hypothesis development, recruitment and ideation at later stages.
This is a PDF of a persona template. It prompts you to think about their age, location, socioeconomics, their bio, influences, motivations, pains and gains when interacting with your product.
This is an example of an audience persona. Recreate this for your user.