Be a contributor in life. Not a bystander, a passer-by or a spectator. Contribute. That means giving. Of yourself. If it is easier for you to imagine that giving means throwing money at every problem that crops up, then you must have a lot of money to throw around and a lack of imagination. An effective means of making a contribution is giving some of your time to cause that is not yours. It is wise in this world to make a space where you set yourself and your agenda aside.
You can contribute your personal expertise humbly, freely, to those that could benefit from your knowledge. You can contribute your time, your ideas, your initiative. Your understanding, your optimism, your smile. As one of the seven billion variations of human being existing on this planet, there is no end of unique contributions you can make to an everyday.
There is a definite payback for contributing. You feel worthwhile. That is a feeling most humans need to feel and when you willingly give, it makes those to whom you are contributing feel worthwhile, too. Contributing is not an aggressive act, it is not forcing your opinions on another, for example. It is a willing, open giving.