I found this little video by DeWitt Jones to be interesting on what he is thinking as he is shooting for National Geographic. If you click on the Blog Title for this post it will take you to the video.
1. Focus your Vision: celebrate what is best in the picture
2. Train your Technique: vision without technique is blind
3. Get in the place of most potential
4. Truly be open to the possibilities: keep looking for the next right answer.
Here is one of DeWitt's columns from Outdoor Photographer that I really enjoyed.