Website or application?
A content website primarily explains information; an application changes and retrieves business state. Some projects combine both. Identify where visitors become authenticated users and which tasks need persistent records. Avoid moving all public content into a client-only app when it can be delivered as readable HTML. Separate content editing needs from operational workflow needs.
Plan the full journey
Sketch the successful path and the ways it can fail. A booking journey needs availability, temporary selection, confirmation, cancellation and conflict handling. Decide what happens when the network drops or another person edits the same record. Show loading and error states in prototypes so these behaviors are agreed before detailed implementation.
Data and access
Define which records belong to each user or organization and enforce access on the server. Browser validation improves usability but cannot replace authoritative business rules. Review file uploads, exports and external integrations as separate access surfaces. Use a suitable authentication provider and define account recovery rather than inventing a shortcut that bypasses identity checks.
Delivery, testing and ownership
Build one useful journey through the interface, API and database before expanding the feature list. Test persistence after reload, permission boundaries, accessibility and mobile layouts. Define the handover for repositories, hosting, migrations and backups. Maintenance and vendor costs should be visible in the scope. Bring a sample task, user roles and existing records to discuss what the first release needs to accomplish.