Edit your Images on Layers

Whenever you want to make an adjustment to your image in Photoshop it is highly recommended that you do any work on a new Layer, and not on your Background Layer. All that you need to do is create a duplicate layer of your background (Ctrl/Cmd J). This is called "non-destructive" editing. Another good reason for working on a duplicate layer is that if you ever want to go back and make further changes to your adjusted layer you can do so as many times as you like, as long as you save your file in the Photoshop (.psd) format. This way, your layers will be saved along with your original background layer.

I am proud to announce that I will be teaching a new course at Learn to Take Photos, the online photography school, starting June 2: The course is called The Creative Power of Photoshop Layers. There's still time to sign up if you want to learn more about this MOST useful feature in Photoshop.