Define the core job
Write one sentence describing the result users come for. Any feature that does not directly support that outcome can be evaluated for a later phase.
Separate essential from useful
Login, payments, notifications and admin dashboards are not automatically essential. A feature is essential when removing it breaks the core journey.
Include measurement
Even a small release needs clear events showing where users start, stop and succeed. That makes the next iteration evidence-driven.
Before starting a project
Use these questions to structure the idea, then send what you have. You do not need a complete technical specification before contacting SDS.