How do you become a makeup artist?

Makeup application is a skill. You may have the skills but not necessarily the technique. A great and cheap way to learn is through a course, unfortunately, courses and beauty school can cost you thousands of dollars. Here is advice I received and it has been incredibly valuable:

1- Get yourself a great, professional level DVD course. It's fun, easy, and MUCH more affordable. I highly recommend the TEMA DVD's because they use several models of different ethnicities which is KEY!

http://www.eventmakeupartist.com/leah.html

2-Get yourself a kit: Fill it with foundations of every color and different types of blush, shadows, lip colors... I suggest saving by opting for eye and lip palettes that have a ton of different colors and drugstore brushes, but spend a little more on high quality foundation.

3-Build a portfolio. Tell models/photographers you are willing to do "TFCD" (Time for CD) which means you will not be paid for your work but WILL get a CD of the photos to use for your port. It's the easiest way to get high quality pictures starting out. A great place to meet industry folk is meetup.com or modelmayhem.com (like facebook for industry)

Once you have these tools I suggest work as many free jobs as you can until you feel very confident and have a ton of pics for a site to show people. Best of luck!