Your newsletter doesn't just have to be about what you do.
If you're an accountant, don't just write about tax. Include info that helps people run a business.
If you're a real estate agent, don't just write about real estate, include other consumer info that people will find interesting.
If you're a plumber, don't just write about blocked pipes, write about other home maintenance topics too.
You get the picture.
Here's a great list of topics about health, beauty, lifestyle and family that would be great in any newsletter aimed at consumers.