I have a really wide head, but a relatively narrow face. I have a lot of problems with fit as well as style as a result. I just went to Costco and tried on every pair of glasses they had, figured out what style looked best, took the measurements off the frames that fit, and used that to order glasses online. Costco's profit comes from their membership fees rather than selling anything, so you don't have to feel bad about not buying anything (since you already have a membership).

The one thing I need to look out for is how the hook on the arm is constructed. One of my ears is slightly farther back than the other (by maybe 2 millimeters). If I buy frames where the arm can't be readjusted the glasses can rest a bit askance on my face.