Tape a couple of dollar bills to a vending machine
Buy a meal for a stranger at a restaurant.
Let the person inline behind you go first.
Give a homeless person a couple of dollars.
Give the grocery cashier a gift card to use for the groceries of the person in line behind you.
Put a bottle of water in your mailbox for the postal worker.
Take cookies out to the lawn service workers.
Buy small bottles of laundry detergent and place in a laundromat with a “Free” note.
Place a basket of sidewalk chalk at a playground.
Always, always, always say please and thank you.