Volunteering is a great way to meet new potential clients, although it is not nearly as quick a method as the previous two.
As a volunteer, you are a peer with other volunteers, regardless of how much experience they may have in their work role. You may have graduated relatively recently from college and have 5 years work experience, yet you are a peer with the CEO who is also volunteering.
You can volunteer with the various Infosec orgs (conferences, user groups, etc.) as they are commonly looking for volunteers. Even as a newbie you’ll meet and interact with senior people in our industry AS PEERS. Others who volunteer now qualify as “People you’ve worked with” and are more likely to hire you. This works especially well when you volunteer for more than a year. Also, working with <fill in the blank> adds a lot of credibility!
You can also volunteer for various good causes: charities etc. You very often will work with high level execs and others (who often volunteer) once again AS PEERS. They may be in a position to hire you or more likely refer you to someone who can, often in their organization. A referral from the CEO of other high level exec carries a lot of weight! Best to volunteer because you believe in the cause.