People belong to organizations
The single most consequential modelling decision is keeping people as records attached to organizations, rather than as standalone rows with a company name typed in.
The moment a contact leaves, a flat list loses the history. A relational structure keeps the account intact, marks the person as departed, and lets the new contact inherit the relationship rather than starting from nothing.
Capture role, not just job title
Job titles vary wildly between organizations and tell you less than they appear to. What matters commercially is the role a person plays in your process: who decides, who signs, who uses the product, who blocks.
Recording that explicitly is more useful than a title field, particularly in deals with several stakeholders where the person you speak to most is rarely the person who approves.
Respect communication preferences
Preferences are both a courtesy and a compliance matter. Which channel someone accepts, what they have opted into and what they have asked not to receive should be on the record and visible before anyone contacts them.
For teams operating under GDPR this is not optional, and keeping it on the contact record rather than in a marketing tool means the person about to send an email can actually see it.
Maintenance beats cleanup
Contact data decays continuously as people change roles and companies. A periodic cleanup project treats a chronic condition as an acute one.
Small habits work better: update the record during the call rather than after, mark departures when you learn of them, and let communication history reveal contacts nobody has spoken to in a year.