Who is the customer?
Name the person making the decision, the problem they face and how they solve it today. A broad market description is not a customer definition.
What must be true?
List the assumptions behind demand, price, delivery costs and repeat purchases. Prioritise the ones that could change your decision to proceed.
What is the smallest useful test?
Choose a conversation, prototype or pilot that can challenge a key assumption. Agree in advance what evidence would make you continue, change direction or stop.