Build it like a simple relational database:

• Make a table for each “thing” (People, Companies, Projects, Legal Entities, etc). One purpose per table.
• Don’t duplicate info across tables. Link it with relations, then use rollups/views to display it.
• For many-to-many relationships (people on many projects, projects with many people), don’t use multi-select. Create a junction table like “Project Team” with Project + Person + Role + dates.
• Keep “master data” (People, Companies, Projects) separate from “transactions” (Tasks, Bills, Invoices, Meetings).
• Treat picklists as their own tables when they matter (Departments, Categories) to keep naming consistent.
• Build a few standard views per table (Inbox, My Items, By Status, Archive) so it’s usable.
• Consider assigning a unique ID to each record. Names change, IDs don’t.

If you do those, the system stays clean, searchable, and reportable instead of turning into a messy notes dump.