Cutting things off at the edge of the frame
Have you ever looked at someone’s photo and asked “why did you cut off their feet or their hand?” they respond with I had never noticed it before. It might not be the feet or hands it could be the top of the head.
Never turning the camera vertically
One thing you often notice with new photographers is that they only use their camera in landscape mode. They never seem to consider turning their cameras to shoot vertically. Try turning the camera vertically and see if you can get a better image.
Centering everything in your images
When you take photos of landscapes, or anything with a horizon line, it is best to put the horizon on one of the third lines. The rule of thirds is one of the computational guides for photography. As you get more into photography you will hear more and more about it.
Not looking behind your subject
There is a tree branch coming out of that person head. You need to consider everything is the frame. You can usually change this by moving a few steps to either side.
Not turning the flash off when it’s not needed
If your at a concert or fireworks show you will see camera flashes going off. There is no benefit to using a flash when you’re photographing something from a distance. Your on-camera flash can only effectively light objects a few meters in front of you.