One very important lesson of good photography is ‘framing’ your subject. This refers to where the subject ends up appearing in the photo.
Now, I am not saying the subject has to be right in the middle of the photo. There is an art to the placement.
You can always crop a photo to center the subject later. Conversely, a bird can be off center if he is in some interesting foliage, or a cityscape might fill the entire scene, requiring you only to figure out how much sky you want to have showing. But, while taking pictures, you should give some thought to what appears in the image. If you are doing a picture of just one head, you should try aiming the camera at roughly the center of the face.
Now that is a good photograph right there.