Before creating a prototype for your product, you first have to envision the outcome you're looking to achieve without worrying about any possible constraints. Then reverse engineer the processes you would have to take in order to get to that vision you initially have.
Every creative is different and has different ways to come up with a multitude of solutions. I consider myself a "lean" creative where I never follow any rules or guidelines. It is a risk that I always welcome as it keeps me motivated and organically open to coming up with solutions without boundaries.