The FAQ page on Paul Nicklen's website is great. He answers the question always asked of him "How do I get published in National Geographic"?
Everywhere I go, people always say, "you are so lucky! You get to wander the world and take pictures for National Geographic." I need to dispel the myth that working for National Geographic magazine is comprised of traveling to exotic places, taking a few snaps, and living a life of fame and luxury.
I was entirely self-propelled in my career development; when I started, I had no "connections." I maximized my personal experiences and skill set (ie. surviving in the Arctic) and shot, shot, shot. For years, I compiled a body of work while sometimes living out of my car in order to afford gear (I still dream of lenses). After pitching my work all over the place, I was published first in local Yukon Territory magazines, and then internationally, and, after about 8 years of repeatedly pitching to NG, I was sent out on my first NG assignment and started a mentorship with Flip Nicklin (no relation). Along with photographer Joel Sartore and editor Kathy Moran, Flip granted me the opportunity to photograph underwater situations on one of their stories (see "Pacific Suite," February 2003). A few months later, I got "the call" - the editorial team asked me to shoot an underwater story for them on Atlantic Salmon for the July 2003 issue. I have been shooting multiple stories and other projects ever since.