Know your scales, then you know your chords in each key; I ii iii IV V vi vii. Then write songs playing with the 7 chords in each key/scale. Add some dissonance to your chords, so not just Perhaps 1357 (Alicia Keys) or 12357 (Elton John).
In the first two parts of Music Theory Basics, we covered a lot of topics. Today we will only be focusing on one topic: key signatures. There are, however, several layers to this concept. I will try an lay it out in a way that makes it a tasty parfait and