All martial arts schools would benefit from aligning with a local charity. The media are practically obligated to cover a charity event. 

Charities are always looking for was to raise funds and awareness.

The value in working with a charity is their list and ability to promote you. They may not have money for promotion but they have a list. You want them to promote you to their list and on their website.

Some larger charities have budgets for promotions that would work great with you.

By offering a project that brings awareness to their cause, they increase their pool of potential donors.

Think beyond seminars and whatever a-thons and get creative. 

Would Junior Achievement sponsor a series of PSAs featuring you giving self-defense tips for students? 

This clips sponsor was a plastic surgeon private student of mine who sponsored this. I did about a half dozen of them. In that case, he was a business and not a charity but he was also a huge fan and wanted to help me build my name.

You want to align with their goals, so study what they are trying to accomplish and offer to team up with them. Look for the “relationships” or “alliances” manager if you can’t see a marketing director on their website.

Do your home work first and go in prepared.