For some time now, I’ve been teaching and using a sharpening technique that leaves a minimum of distortion or artifact, and permits application of sharpening only where it is most needed. Here it is, step by step:

Here’s a screen shot from Photoshop with the image opened and the panels in place:

Next, duplicate the layer you are working on:

Apply the High Pass filter to the new layer. Start with an intensity of 2.0:

Next, change the layer blending mode to Hard Light.

If you wish to sharpen the entire image, you could stop here. If the sharpening effect is too intense, lower the layer opacity to suit. Alternatively, you can create a layer mask that temporarily hides the sharpening effect. One way to do this is go go Layer>Layer Mask>Hide All. You’ll see a black rectangle appear next to the layer icon:

Now, if you want to sharpen selected parts of the image, select the paint brush tool, and set the foreground color to white. Now, paint on the image in the areas where you want the sharpening to appear. You can control the intensity of the sharpening effect by adjusting brush opacity. Note the brush circle below, which includes an added red dot to help identify it.

If you brush over an area that does not need sharpening, change the foreground color to black, and paint over the area again. This will hide the sharpening effect. Now you have selective control over sharpening, and a new method too!