Good to see someone getting into the volunteer spirit!
Once upon a time I was a member of a local Lions club. It was a very busy four years, but the effort was well worth it. The club did things for the local hospital, disadvantaged children etc. Very rewarding stuff - is there a Lions or similar service club near you? Service clubs are good, because they firstly introduce you to local areas of need, and secondly, you go in with a group to support you. Most of them rarely ask more time/effort of you than you are willing to give.
At the moment my gf and I are heavily into volunteering as emergency medical staff for motorsport (specifically motorcycle racing, although we hope to expand our horizons into car races) events. It's a good outlet for our skills (we're both nurses) and also good experience. Plus the added advantage of hopefully saving a life or two. And, yes, we did, just the weekend before last. We're both mad-keen MC race fans, so we get to see a side of it most fans never dream of. I know it's not doing a lot for the community as a whole, but we already work in public health, so it's a change for us, plus it gives something back to a sport we both love.
Good luck whatever you decide.
Cheers
Jewel