A great way to promote your business is to give a class. You can create a workshop or class and give it at a local community center. You could also give a presentation to an existing class. For example, several times of year I give a presentation to a class of Interior Designers when they’re learning about marketing.
Be sure that you provide value, and that you aren’t holding back. Additionally, you don’t want the presentation/class to seem like a sales pitch.
Here’s a funny video about Power Point Presentations.