If i see someone who needs cheering up, whether it's a stranger or one of others, i will take a moment to make that person smile, whether i tell a silly joke, smile at them.
Don't just let those old sweaters or clothes sit in your closet for years. Take the time to sort through clothes sit and to donate them to charity so that someone else can find a good use for them. It won't take long to sort through them or to drive them down to where they need to go, and you'll feel good just thinking about someone else finding a better use for your clothes.