One of the easiest ways to improve your photography is with careful attention to framing. Look into the corners of the viewfinder to see what is there. Do you need all that background? Can you get closer to your subject or zoom in? Would the picture look better as an upright or landscape?
One common mistake beginning photographers make is not filling the frame with the subject. Before you click the shot, pay attention to the background. If you have a photo of your subject waving in the door, beware that you don’t get the neighborhood and just a tiny waving blob in the middle. Get close and get the subject and a little of the door and forget the whole neighborhood. Watch out for clutter in the background and that pole growing out of your subject’s head. Also watch the lines of the composition. Which way will make them work best? Can you use windows or doors to frame the subject?
Still, even with all that attention, you may need to crop.