Before an interview for a volunteer position, take some time to prepare and put your best foot forward. If this starts to read a lot like advice for a "real" job interview -- it's not an accident. Volunteering is not just something you do to gain experience and build up your resume; it may actually lead to a real job offer. As such, treat the entire process with the same amount of professionalism as you would any other interview. And if you're the manager tasked with interviewing a potential volunteer, choose carefully -- even volunteers can make your company look very good, or very bad.
At the interview, both the company manager and the volunteer candidate need to demonstrate that they're committed to and invested in one another. If you're the hiring manager, take some time to review the candidate's resume thoroughly to make sure the person is the right fit for the organization, and that she possesses the skills that will help her succeed. If you're the volunteer candidate, do some homework about the organization and have a good amount of knowledge about what it does on a daily, monthly or yearly basis.
Once both parties have done that initial research about each other, it's time to talk about proper placement. If you're the manager, ask the candidate what type of role she sees herself filling. If you're the candidate, have some ideas about the work you want to do with the organization and where you want to be placed. Be as specific as possible. Always show a positive attitude about the organization and the work it does. In some roles, the volunteer may have to complete a background check to start work; discuss this and any other logistics about the volunteer's placement.
Just because you're not going to get paid -- or you're not going to pay this person -- doesn't mean the volunteer and organization have a get-out-of-jail-free card regarding professionalism. If you're the candidate, you need to show up on time, be appropriately dressed and show enthusiasm for the position. If you're the company manager, meanwhile, you need to treat this person with respect and provide clear goals and outlines for what the position will entail. Think of the entire volunteer experience as the "ultimate interview," advises The Ladders career website, giving both sides the opportunity to find out more about the other and decide whether a paid position is in the future.
The volunteer interview should definitely include some talk about the amount of time involved. If you're the volunteer, let the manager know when you'll be available for work and how long you expect your volunteer position to last. If you're the manager, be realistic about your volunteer's commitment; don't ask her to work grueling hours or in unsafe conditions -- that will likely lead to burnout and the need to start the search for a new volunteer all over again.