Often times on set, a photographer or stylist will reference an iconic photographer, a style from a specific time period, or a celebrity/model from the past. It's important that you know what they're talking about.
Years ago, I bought Way Bandy's book on the suggestion of Paul Starr. After that, things changed.
The more I learned about make up, the more I wanted to know. I used to spend hours looking at vintage magazines at the Hollywood library. Now I spend hours on blogs, forums, and websites that have archived these images and made them readily available.
Although I'm not going to do all the work for you, my tumblr page has turned into somewhat of a "virtual moodboard" where I post images (and other things) that inspire me.
Check it out, and research vintage make up looks and artists on blogs and fashion forums.
At the same time, be sure to keep up with current editorials as well. If you don't have the money to buy a bunch of magazines, go plop yourself down in the magazine section of Barnes and Noble for a few hours every month! I promise you'll notice a huge difference in your work when you've done your research, and you'll start to develop an aesthetic that's all your own.