I like to sometimes purchase something extra from a vending machine when I go to one on campus and leave it there for whoever stops by next. I got inspired to do this when I was having a cruddy day, and two bottles of pop came out when I paid for one at a vending machine that day. It was just a nice little surprise that lifted my mood a bit, felt kind of lucky, and I thought what if someone had just left one there, initially, and that's how it happened? So I'd like to share that little boost with people.
I'm big on trying to get lost things back to people, too. I've had a couple of times where I've found people's flash drives in the library, and I'll get it to the lost and found and put a note by the computer in case they come back. Again, I especially like to do this because I've lost important things at the library before, only to pick them up at the lost and found later, which is a nice feeling.
For a third thing, I make sure to have courtesy on the city bus. Like giving the front seats to people who need them. You're technically supposed to, but you only really get made to move if someone with a wheelchair comes on. Also, if I see someone trying to press the button for the bus to stop and it's not working, I'll push the one next to my seat for them.
Little things are definitely a big deal!