Check out the LIFE magazin series about taking great pictures. I found it today and liked it very much. Full of good tips about triangular composition, leading the eye, and how to take photographs in Hitler's bunker.
Not kidding about the latter. What might be even more interesting than war correspondents studying blood stains on the Führer's sofa is that they included some of the original captions in the gallery, where the photographer describes what's on the film rolls. A good reminder that self-administration is as much of a part of photojournalism as is taking pictures. And how hellish it must have been to do this on typewriter... but then we all know that war is hell.