1. Decide the model before importing anything
People sit inside companies. Agree whether you sell to individuals, organisations or both, because that decision shapes every report you will build afterwards.
2. Agree a short tag list
Six to twelve tags covering industry, city or region, product interest and status. Long tag lists get used inconsistently, which is worse than having none.
3. Import in batches, with a preview
Load one source at a time so you can tell where a problem came from, map fields deliberately, and check a sample of records after each batch.
4. Merge duplicates rather than deleting them
A merge keeps the call history and messages from both sides. Deleting a duplicate throws away the conversation that made it worth keeping.
5. Assign an owner to everything
Unowned records rot. Ownership can be by territory, product or account, and it should be obvious on the record who is responsible.
6. Keep it current by capture, not by cleanup
Forms, the dialer and the WhatsApp inbox create records as work happens. A database maintained by capture stays clean; one maintained by periodic cleanup does not.