Here's my mental cultural checklist for each country I visit. I'm not super strict about it. I just try to let things happen naturally and I've rarely regretted it!
• Ride a public bus and/or train
• Eat something local from a street vendor (preferably cooked/avoid meat)
• Buy & try local fruits, veggies (preferably peelable)
• Learn to say Hello and Thank You in the local language
• Talk to at least one new person each day
• Visit at least one museum
• Visit at least one park/green space
• Look for local street murals and/or public art
• Drink a local beverage (non-alcoholic, usually tea)
• Participate in local events/festivals or volunteer for local organizations when possible
What's something you enjoy doing to enhance your travel experience?