Who is the customer?
Start with the customer. Whether you have well defined personas or use See, Think, Do, Care to understand your total addressable market, understanding who is your customer is always the first question to answer. Not even Amazon can sell anything to anyone.
What do they want that you can give them?
What products are those customers looking for? What products do you have or want to develop? Some products are essentials, some more desirables. Some products are bought every day for a lower price, some are bought once in a life time at a high price. There is no gain in trying to provide something that those customers don’t want.
Where do they go to get it?
People looking for a brand-new top-of-the-range Ferrari don’t look on eBay, they go to showrooms. People looking for a sandwich go to their local supermarket or sandwich shop, they don’t go to a builders merchant. Customer’s already have assumptions and expectations about what they can get where. Are you going to go where the customers are or try to disrupt that and take somewhere else?
Why would they want to get it from you?
What’s your USP, what differentiates you from your competitors, what is going to make those customers come to you rather than go somewhere else? Is it your superior quality products, is it your customer service, is it the image a customer creates when using your products?
When can you give it to them?
Do you have existing products they can get now, or do you need to develop something? Are you going to provide an MVP in one month or a finished thing in two years?