- Analyze songs that you like. While reading sheet music (as other's have mentioned) is certainly a good approach, take time to find songs you actually enjoy listening to. If the song is guitar driven (as many are in today's popular music), you can find "tabs" online. They're a little weird to decipher at first, but you'll be able to extract the notes, and transpose it to piano.
- Then take a melody, for example, and play it back. What scale degrees are they playing? Did they start on something other than the I (or i)? What part of the melody did you like, specifically? How did the melody change over the course of the song? Lots of little lessons to be learned. You can apply this to chords as well.
- Next, pay attention to the rhythm. I find this part left out of a lot of discussions surrounding music theory. When you play a note is as important, or often times, more important than the note itself. There's a seemingly infinite number of ways to play even the simplest set of notes.
- Finally, just play. Take whatever small lesson you learned, and improvise something. Over time, you'll commit all the little things you like to memory, and the music will just flow out of you (sorry if that sounds corny).