Many people will suggest that writing for nonprofits as a volunteer is a good way to build a portfolio and client list. But instead of positioning yourself that way, I suggest that you write or edit for a reduced rate or make it clear that you are donating your services as a professional freelance writer. By framing the relationship this way, it is clear to the nonprofit that you are a professional freelancer who normally expects payment for services. Asking for payment on future projects will be much easier with this kind of relationship in place.
