There is alot of people that learn to play piano mainly by memorizing chords and just playing out of a fake book. Which is alright if that is as far as you want to go. But to really learn how to play the piano you really need to learn music theory.
With this understanding you will not just be able to blindly play songs out of a book. But you will understand the principles of why you are doing what your doing. This is so important because if you understand why then you dont need a book to tell you what chord, or note to move to next. To me this is one of the most important things that I did to help me learn the piano faster then I would have by just learning how to play out of books. The most key principle of music theory is to understand the circle of fifths and more importantly, how to apply it. The gospel keys 202 piano course is really a fantastic course on this principle because you will learn exactly how to apply this concept. This course breaks down the circle of fifths in a new and unusual way and shows you exactly why this key pattern is the same pattern that most all songs are based off of. If you want to really learn this key principle to understanding how music works and how to apply it to every song you would ever want to play on the piano then click here to find the gospel keys 202 course to learn. And you will also find more gospel piano lessons there to.