I guess the first step would be to reach out and meet people from the organizations of interest. You might see if there are local events where you might network. Perhaps a local conference or presentation. If there is a specific topic of interest, see if there is a local coalition or collaborative that meets, find out when and where they meet (and whether membership is open), and go. Do some research on the various organizations and individuals before you go.
Another strategy is to find out if there are opportunities to volunteer.
If you have decided on a couple of organizations that are interesting, simply set up informational interview meetings to learn more. Keep them short and have a set of prepared questions - in other words, make sure the meeting has purpose.
The Community Tool Box Advisor