As powerful as Photoshop is, there is little about the program that is obvious. Case in point: How do you rotate a layer? Right-click on it and select Rotate? Choose Rotate from the Layer menu? Click on the Rotate tool? The answer is no, no, and no. Fortunately, there's the Free Transform command, which rotates the active layer and much, much more.
Photoshop offers lots of tools for automating selections, but two stand out from the pack: The first, Refine Edge, lets you modify your selection using five different parameters and preview the results in five different ways.
The Levels command, and its cohort, the Histogram, let you adjust luminance levels on a channel-by-channel basis. The upshot is that you can increase contrast, correct for color cast, and make a bad image good.