I was never taught the different ways to contour and highlight various eye and face shapes, so I've devoured everything I find online and in makeup books. It is hugely important to analyse the face and decide where you're going to place the makeup...what to enhance and what to hide....rather than just "copy & paste" the same look on all your models.
It's a nuance in skill that most people (even clients and colleagues in the industry) may not notice but quality shows and you'll find that even though the makeup might be the same, your models will always look their best.
I find a lot of these on tumblr which I reblog, so make sure to follow me on TUMBLR for more useful little snippets like these!
Source: Here, here, here, here and here.