Take successive photos of your subject if there is a chance that it might move. Certain subjects, such as wild animals, won't just wait patiently for you to take your photo. In this case, take one shot quickly so that you have something to work with. Then, if the subject hasn't moved, take more shots with better positioning and composition.
If you’re interested in becoming a photographer, here is some insight for you on why I think it’s a great career choice!