Digital photography is doing for photography what the piano did for keyboard music. You can still play music composed for the harpsicord on the piano but not the other way around.
Most of the pictures today still follow the rules that came about because of the limitations of analogue photography. The exposure must be just right, even in black and white there is a limit to what you can do with the negative once it is developed. With digital photography much of the picture making, and fun happens in the editing after. Many of the photography tutorials are about manipulating the picture, much in the same way as when sound came to the movies and musicals.
A camera record light in a very different way than the eye sees. For me the learning process is to try predicting the way a light sensitive surface record light.
I do not take pictures with a predetermined subject because it implies a caption or theme. My approach is to try and keep my mind as blank as possible, looking at the light and what happens; visually rather than verbally. The exact timing is also important because that distinguish photography from all the other art.