Notice and tell a parent when one of their kids is polite or caring, especially when they think no one is watching.
Let someone with just a few items go ahead of you and your full cart
Speak on a topic you know to a community group who wants to learn
Pay for the person behind you in line - at a toll booth, a drive-thru window, the coffee shop, etc
If you have an elderly neighbor or friend, offer to help with yard work like leaf raking or shoveling snow
Bring your neighbor's garbage cans up from the end of their driveway
Make it a point to pay someone a sincere compliment every day
Offer to put someone's bag in the airplane overhead, or take it off of the carousel at the airport.
Offer sunscreen, wipes, tissues, or hand sanitizer to someone who looks like they might need some.
Write an inspirational note to someone who needs inspiration.
Help that mom that's struggling to get her stroller through the door.
Sit next to someone who is sitting alone at a meeting, school function, work event or kid's function, etc.
Rescue a wallflower! Strike up a conversation with someone who's standing alone at a party.
Offer your mail carrier a cold bottle of water, a glass of iced tea or a $5 Starbucks gift card.
Drop off combs, hairbrushes, toothbrushes, and toothpaste at a shelter or a soup kitchen.
Shower the pediatric wing of a hospital with coloring books and boxes of crayons.
Bring flowers to a nearby nursing home - the nurses will know who needs them the most.
Leave an extra generous tip for a good restaurant server.
Let a fellow driver pull out in front of you in traffic or merge into your lane.
On a crowded train or bus, offer your seat to someone who may need it more than you do.