You can count a trip as a business trip if the "primary" purpose of the trip is business. Primary purpose means that more than 50% of the reason for the trip is business. This includes children's field trips, trips to the bank to deposit parent fees, and trips to trainings. A trip to the grocery could be claimed as a business trip if more than 50% of the food purchased was for the business.
You must have an "adequate record" to show that you made a business trips: calendar notations, receipts, cancelled checks, credit or debit card statements, field trip permission forms, training certificates, mileage log, photographs, and other written records. You may want to review these records monthly to make sure you've identified all your business trips.