Wait to do this until you have at least finished pushing the shutter!
I have noticed when people are beginning to formally learn photography they can be impatient with seeing how their shot came out. I see this behavior when they are shooting. It seems almost before they have even finished pushing the shutter they are already looking at the back of their camera to see how bad the shot came out. I always discourage this behavior and encourage taking your time. Pushing the shutter on your DSLR, and thus starting the action of making a photograph, is a lot like a swinging motion. The follow-through is important too.
So when you push the shutter, push it and follow through by holding the shot, by exhaling, letting thoughts flow through your mind about what you just did, and then review your shot on the back of your camera. If you are so hastily looking at your shot after you take it then you were not ready in the first place to even push the shutter. Prepare more before pushing the shutter so you know what to expect after you do.