Again, the power of Photoshop is not that you can make changes to an image. After all, there are only a couple of things you can actually do to a bitmap-

1. Change the value of individual pixels

2. Copy pixels from one location to another

The REAL power of Photoshop is being able to control which pixels get changed it what manner.

Masks and selections are the way you have control. Most people think of a selection as starting with the lasso or marquee or magic wand. Sure, that works. But you have another powerful option- the image itself.

Say I want to make changes to only the highlights in my image. How do I find and select them? Should I individually lasso every pixel over a certain brightness?

Or maybe I already have that information available. I can use the image itself- it already has different values for shadows and highlights. So I create a luminosity mask from a channel, maybe apply a curve or filter to refine it a little bit. Since masks are simply an 8-bit channel, they look like a greyscale image. Light areas are NOT masked, dark areas ARE masked. Voila- I've selected the highlights, and I didn't use any actual selection tool.

Obviously it gets more in depth than this, but once I stumbled upon some of these concepts I've found masking and selective changes to my files to be MUCH easier.

Clone stamp tool - *waiting to be trolled and flamed*

But oh come on... Very few people have perfect face, even after makeup applied to them.