Most of my clients understand good typography design, which is nice for me. But, there is a small handful that do not, and I need to fill them in on correct typography usage. Don’t get me wrong, I don’t expect my clients to know proper kerning or leading [or known as vertical spacing these days], or even the difference between a font and typeface. And then there are the emerging graphic designers that haven't had enough experience with typography to understand the do's and don'ts—I've seen it plenty of times at student portfolio reviews.
Small businesses or solopreneurs don't have the luxury of time to learn how to pretty typography, if they can't afford to outsource to professionals. However, they should at least know about the hierarchy in the presentation of fonts.
I've created this simple typography guide [with a touch of humor] just for them and the former in an infographic here below, and PowerPoint slides on SlideShare. I'm a true advocate for good design and good typography, and I have to admit that it does bug me when it's done incorrectly, or in bad taste. I'm no design snob, I just have a sixth sense when it comes to refined design.