3. The last super-efficient tip is the color range. If you have a more complex image, you and you need to select some reds or highlights or more. You can do that very easily. Select the layer and go to the selected tab in navbar. Find color range and Click it!
You should see a new window with a color range. Find a small triangular and see what staff you can select. You have their reds, yellows, blues, crimson, shadows, and more!