Here's how I got started:
1. think of your talents and experiences that make you, who you are.
2. Start small...do the research of possible charities, clubs, organizations, community and world-wide projects that interest you, the internet is awesome for locating ideas.
3. Decide who, what where will benefit from your talents.
4. Make a call or visit the organization to get more details of how you can contribute.
5. Set aside time each week or month to be actively involved.
6. Reap the satisfaction of seeing a project from start to finish and you will be amazed at how great you feel and how those that you have helped will be touched by your efforts.
Above is what I have been involved with: