I leave other people alone. Trust me, it's probably the nicest thing I can do for them.
I also have a habit of occasionally buying people small things, whether I have the money for it or not. I do a lot of small things around the house as well to make life easier, but then, I live here too and people do small things like that for me too, so that's probably more of an unspoken "give and take" sort of thing than a random act of kindness. I'm generally not very good at these things.