One way to make the world a better place is to offer to go grocery shopping with a disabled person so the person has assistance pushing the cart and carrying the groceries. Another idea is to spend some time reading to or chatting with an elderly person.
People who are shut-ins due to factors such as old age or illness often appreciate help accomplishing simple tasks their shut-in status prevents them from accomplishing on their own. For example, it's thoughtful to ask if the person wants or needs something before heading to a store or pharmacy. The individual may need something as simple as allergy medicine or a new tube of toothpaste, and offering to pick up the item is a great way to make that person's world a better place. Such individuals often also appreciate someone taking the time to stop by and play games or simply talk with them, as being confined to the home can be lonely.
Making an effort to compliment others on a regular basis is another gesture that helps make the world a more pleasant place to live. Compliments are especially effective when they are specific to the person, such as saying, "You have a true gift for making jewelry. That purple beaded necklace you made me last Christmas brings out the best in so many outfits!"