When creating start with the smallest complete version you can create.
Having that version that is complete in itself allows you to start the process of refining. You have a starting point and an ending point.
An artist does this with his canvas. Even with a white canvas, the beginning and the end is there.
I follow this process for budgeting. The small is money in, money out, and money saved. Once I have that figured out I can go to the next level down. I can continually refine until it is at the point where I need it.