Here is a great
article that was posted on ProVideoCoalition.com for young or aspiring Director's of Photography. Probably the best takeaway is the idea that experience is the key. While study and schooling are important, there really is no substitute for actual experience on-set. Knowing how to assess any situation quickly and come up with the right solution is what makes one sought-after as a DP--and comes only from having faced similar situations in the past.