Although there might be small tips and tricks that will nudge the percent viewed on your email sends, all of that is basically laughed at on the developer end. Recruiting emails with “catchy” subjects and salesy pitches are a running joke in the technical community. There’s been discussion of going to interviews dressed as ninjas and rockstars just for fun.
Material Design uses the metaphors of digital paper and ink as a foundational principle. Structuring interfaces as if they were made of individual sheets of paper with ink printed onto them helps the user form mental models of how the interface works, where things are located, and what kinds of behaviors they can expect as they maneuver through an app.
To further help this model, UI elements can use "elevation" to show how close or far away they are from underlying layers like the canvas with elegant drop shadows.
It makes sense then that lighting should play an important role in thinking about your interface's material design.