Sharpening and the various techniques available to apply it are hotly debated topics. Everybody has their own favourite way of doing it, and they tend to stick with it. I certainly have mine. I’ve got 2 or 3 go-to methods I bounce between depending on the image in question. There are also techniques I don’t use because I just don’t like what they do.
This video from Jesús Ramirez at The Photoshop Channel covers pretty much every main method of sharpening images within Photoshop. How each of the different methods work, their advantages and disadvantages. He also talks about the different times during a photograph’s life when you’d actually need to sharpen an image.