Almost anything you do in Photoshop can be done with more precision or just to a better degree if you are familiar with how to utilize selections. Whether you’re retouching a body, a face, building a composite, subtracting elements from an image, adjusting skin tone, altering clothing and a torrent of other things, knowing how to make good selections will open up the taps on what Photoshop can allow you to materialize.
The problem, however, is that manipulating them isn’t very intuitive and require of you an understanding of how Photoshop behaves, but that’s where this video should help.
It certainly helps to have a grasp of what a selection actually is, and according to Adobe,
A selection isolates one or more parts of your image. By selecting specific areas, you can edit and apply effects and filters to portions of your image while leaving the unselected areas untouched.
Understand too that pixel selection can be done with a number of tools from the set of ‘Quick Selection Tools’, marquee, lasso and so on, but a selection can also be done via a color range, and even vector data. But don’t get bogged down in that, just know that selections can be copied, moved, and pasted, or saved and stored, made into masks (which are like inverted selections) and all of this in an effort to help you get the image to look how you want.
The video herein by Anthony Morganti is near-as-makes-no-difference 30 minutes, but he sort of holds your hand like guardian and guides you through much of what you should and need to know for typical photo manipulation, and you get a basic lesson in layers while you’re at it. Check it out.