Lots of good suggestions on the technicalities of how to manipulate the information when it isn't what you want. You have to know the capabilities of yourself and your tools. If you don't have all the tools then you need to figure out how to work around that shortcoming. If you are taking shots that push past the boundaries of your camera then you need to shrink that range with lighting or filters or expand that range with HDR or similar processing with other tools. I don't think anyone has mentioned my usual method for landscape light problems so to the very good responses above, I'll just add - wait. AM, PM, noon, sunny, cloudy, tomorrow, next week, whatever. Problem areas are usually lessened by cloudy diffused light or at the least, are easier to deal with.