Budget, time, scope, length.
Before starting a business project set some constraints. They help chain your efforts.
If there's no deadline you can keep procrastinating. No scope just add stuff to your wish list, keep adding features. No defined budget means that you'll do everything yourself or you'll outsource everything. Without them there's no clarity, no priorities.
There are other types of constraints. Maybe more important.
How do you want to feel about:
These help clarify your intent and your strategy for a project. If you want to make a business out of it.
p.s Working on something just for the sake of it? By all means. Those are fun and different than creating a business.