Stop copying photographs!
Seriously, I keep seeing this. Even in tutorials, I see image after image that is just reproducing a photo. The point of photo references is not to reproduce the photo, but to use it to help with an image. The key word there, is "help."
Think of it like writing a paper, for school. If you just copy the encyclopedia entry, you're cheating and you're not really learning much. The point is to use multiple sources and points of reference to create something your own, hopefully something new.
Copying a photograph or another painting or drawing can be a useful exercise. But that's all it should be: exercise. If all you know how to do is copy photographs, what are you going to do when you don't have references? Anyone can copy, it takes an artist to create, from nothing.