What an idea usually needs most is contact with reality. Make it small enough to validate end to end, then start building.
Describe one complete experience
Use one sentence to describe the user, the situation, and the outcome. Then walk the whole path: where the user enters, what they need to provide, and how they know the task is complete.
Build the smallest reliable loop
Reuse capabilities the project already has. Keep the interface clear, validate inputs, and make failures explainable. Reduce feature scope without reducing the reliability required to finish the one job you chose.
Let real usage choose the next step
Run the product in an actual scenario. Watch where confusion, waiting, and errors occur. Fix the problems that affect the outcome before adding new capabilities.
Leave every iteration with runnable checks and clear notes. The next time you return to the project, you should be able to continue building instead of reconstructing what happened.