1) Google "Music theory" + <"EDM", "beginner", "advanced", "circle of fifths", "songwriting", "writing leads", "writing hooks", "secondary dominants", "tritone", ... and so forth>
2) Read over one or four of the links you find there for new information.
3) Put your hands on your MIDI keyboard and figure out with your fingers how chords look. Better: actually play! This enables you to hear emotional feedback on how things "feel".
4) Repeat in a few days in search of something new. If you find a term you don't understand popping up repeatedly, add that to your list of things to learn more about. I had a lot of fun learning about 7ths this way. (
http://music.tutsplus.com/articles/secondary-dominants-and-how-to-use-them--audio-2663 ! )
try http://www.hooktheory.com
This is a great place to observe what other artists do that you aren't even trying. For instance, I used to change chords every bar. Turns out there's plenty of tracks that don't.