Volunteer in 5 areas and you will always be busy. In time you become the leader, the committee chair, the president of an organization.
Give Blood.... Join the Coast Guard... (Or CG Auxiliary) Shop Local, Buy Made in the USA goods as much as possible.. (I'm assuming you are in the USA)... don't drive a Foreign Car. Take Mass Transit when ever possible.. recycle... Keep yourself healthy so that you are not a burden on the systems. Volunteer fire Department is you live out in rural parts of the country...
blood donation, volunteer, give your time and compassion in crisis centers
you could always work for a company that has strong culture of charitable giving, there's a few out there that match donations for example. You could also join a service organization/club they're usually involved in lots of that sort of stuff