Here are some essentials to remember:
Food and water. You need to bring enough for the trip. Food and water outside could cost more than when you pack from home. I bet I need to bring even our breakfast coz assembly time in school is 5:30 AM. I'm now thinking of pre-cooked pasta in the evening that will be heated on the day of the trip.
Pack your things the day before. Wish I can really follow this. A list may be necessary and helpful so as not to forget important items.
I.D. I'm glad this was noted in the diary as I tend to forget this very important thing. A small problem though coz Zach has lost his school ID. I should put my ID first in the bag.
Pen and paper. For taking down notes.
Toys or books. To beat boredom during the travel.
Camera. Moments can't be taken back so they need to be captured.
Don't bring anything that won't be necessary for the trip as it might just get lost.
Silence. In appropriate places like museums, as others might also be visiting and observing.