I have been stuck at home now for nearly 6 weeks. Maybe this is an excercise to combat boredom, but here goes...
This happens in at least two ways (probably more). When you get your camera to do some photography, it can be planned or unplanned. By this I mean you can choose your subject or you can find your subject.
Planned subjects are nearly infinite - there are lots of them. People, children, horses, barns, natural beauty, flowers, animals, interesting buildings or structures, events, cultural diversity, graffiti, icons of the world, sports - the list goes on.
Unplanned subjects are those you were not expecting. Fires, storms, weather, accidents, acts of kindness, acts of terror, crimes, acts of love, unusual light, rainbows, lightning, animal interactions, and other unexpected things.
Learning to see; having good photographic vision is the result of experience, studying art and photographs of others, trying new subjects and developing a sense of what is striking, beautiful, emotional, funny, or interesting. It is a little like trying to explain how an interior decorator can transform a room into a thing of beauty or an interesting space.
I don't think you are born with this vision; I believe you can develop it with effort, hard work, study and experience.
Also, there are high key and low key images being made. These can be useful techniques (as long as they are not overused). Low key photos concentrate the tones in the photo to the darker tones and high key photos concentrate the tones in the photo to the lighter tones.
When you are photographing a subject that is among tree branches or plant growth, if something is between you and your subject the lens will focus on that something and your subject will be out-of-focus. For example, often when shooting wildlife, grass or other vegetation or tree branches will cause fuzzy or soft photos of the animal you are trying to photograph. This is one place where manual focus may be better. Shooting in low light can also require manual focusing.
There are creative ways to use focus to achieve an effect in your photograph.
You must learn about depth-of-field which is the area that will be in focus. Several interesting "looks" can be achieved using a shallow or a deep depth-of-field. This is a skill needed to help you create great photographs.
You must not be a color photographer or a black and white photographer - you must be both! Use color when your subject contains lots of color. Use grey tones (known as black and white photos) or monotones when your subject contains little color. It is really that simple and yet it is not easy at all.
I fight with myself as to when to produce a black and white image. Like many people, I am oriented to color photographs. Even when there is very little color in the scene, I can be very reluctant to go to an image of black, white and grey tones. It is a resistance that I battle with often. And you should as well, because color photography begins to lose meaning when the images contain very little color.
All of these elements taken together influence the creation of a great photograph. Great photographs should be rare. I strive (and often fail) to create high quality photographs. But very few rise to greatness. And that is fine, because if many photographs are great then the word (great) becomes meaningless.