This is somewhat specific to people with experience working on the full stack of a product - from frontend to db design. I want to understand how you start approaching a solution.

What's your favorite starting point - the frontend/UI/UX, the server, or the DB design? As a practical example, suppose you have an idea for a solution to a problem you wish to build out. How would you start about it - with frontend mockups, or with a db design?

Are there recommended approaches / best practices for the scenario where one person is building the full stack? Or is it just a matter or personal preference? I assume standard practices (agile, etc.) are too elaborate for a single person (are they?).