Record start and end locations, total miles or kilometers, and purpose, then keep occasional photos of odometer readings for credibility. If you batch trips, list clients touched. A short weekly log beats epic catch-ups, and mapping tools reconstruct routes when doubts surface unexpectedly.
On the receipt or attached note, name attendees, roles, and the business objective, not just lunch. Highlight pre-meeting emails or agendas showing intent. When scanned together, the story becomes obvious, and you avoid awkward explanations that force you to relive vague scheduling mistakes.
For internet, phone, or software shared with personal life, document your method, such as time-based or usage-based allocation, then apply it consistently every month. Save a one-page rationale. Consistency persuades reviewers, and you will thank yourself during long nights before deadlines.