Sales. One component of your profit margin is your sales. Generally, the more coffee you sell, the higher your profit. There are a couple of things you can do to make sure your sales are as high as they can be. First, serve quality products. Second, hire a friendly staff.
Here, Annette Bening is in nerd glasses, those thick black frames that have become increasingly popular over the past 4 years (or so). You can see how her look is instantly transformed from the previous picture, just because of a change in frames. 3 of 19 Show All.
However, the lightness and stiffness of aluminum in some eye glasses designs offers great advantages. For example, for metal frames that are thicker in design, and larger in design, aluminum is the toughest material and can accommodate the thickest and heaviest lenses. Aluminum frames last a long time and can take a lot of abuse compared to plastic frames, or thin metal frames.