This infographic shows a lot of what goes into a good font. More than that it enables you to talk about it. I do not agree with all of it. But it is very good. For example, for me aperture is about the openness of the c, s, and characters like that. The poster calls the opening of the u the aperture. We’re probably both right.
It’s copyrighted or I’d put it in this posting and talk about it. But you’ll like it.