What Makes a Photograph "Good"
Exposure is the amount of light that is recorded by your camera's sensor. If too much light comes in, the photo will be too bright, and if not enough comes in, it will be too dark. Proper exposure is the amount of light that gives you the results you want. Your exposure is controlled by three factors: the length of time the shutter is open (shutter speed), the size of the opening in your lens (aperture), and the speed of your camera sensor (ISO). You can change any of these settings manually and balance that change by adjusting one or both of the other factors. This will change the look and feel of your photograph. I've made a page called "Exposure" on this blog with posts related to exposure.
Composition refers to the design of your image. We'll use this term loosely to include all of the factors (outside of exposure) that contribute to the look, feel and design of your image. This includes the placement of objects in the scene, the quality of lighting, colors, the sharpness of the image, and many other factors. Sometimes we talk about "rules" of composition, but this is really a misnomer. Composition has more to do with conventions that correspond in some fashion with the way our minds perceive beauty. But sometimes breaking the "rules" creates as much interest as following them. I've made a page called "Composition" with blog posts related to compostion.
Interpretation refers to the intangible quality of photographs that cause viewers to respond in various ways. I believe there is an internal element of photography. It's not just about getting a pleasing composition and exposing it properly. It's about being aware of what's going on inside you when you see your subject, being able to interpret your own reactions, and knowing how to capture that in an image for others to see. This cannot be quantified by f/stops and rules of thirds, though understanding of both may be required to interpret your subject in an image. One of the greatest joys of photography is when your photograph makes others think and react in ways that somehow correspond to what was going on in you when you took the picture. I've made a page called "Subjects" with blog posts designed to help people interpret different kinds of subjects.