There are a number of lessons within Reliable Education's 'Zero To One On Amazon' course that specifically addresses product selection.
Once your product meets many of the criteria shown in the lessons, we have a research process for you to follow. This is where you collect specific data from other listings on Amazon to establish that there is an opportunity for your product there.
We also recommend Reliable Education students form or join a mastermind group with other students so they can discuss granular detail such as which product sample do they like better etc.
Students should do this only once they have thoroughly completed all the Reliable Education Academy modules so they can contribute equally to their fellow mastermind members. Masterminds have proven instrumental in accelerating student results.