How often do you take a walk in your neighborhood? This could be your neighborhood block, your local park, or nearby beach where people can enjoy the great outdoors. You could be walking with your friends, your partner, or maybe your pet. This is a great opportunity to do a little something extra, with zero effort at all.
As you are walking anywhere in your hood, if you see discarded trash (like bottles or wrappers or paper), simply pick them up and dispose of them at the nearest trash/recycling bin. Or, you can carry a bag with you and easily dispose of the items you pick up when you get home.
I've seen some communities go as far as to organize a community clean up, handing out reusable bags, gloves, and grabbers for gathering trash. Do as much or as little as you like, and either way you're guaranteed to make a difference in the place you call home.