To create a good product you need to try.

First, try the product.
There’s no way you can build a good product without trying it first.
Be the user, use it, solve it your own problems until you are fully satisfied with the solution.
Keep it real, be honest with yourself.

Secondly, try harder, fail without fear.
You must test, you must try, you must sell without malice.
Be the owner you want to meet when you enter the shop, smiley, lovely, open to questions and critiques.

Then you must learn how to scale.