Chord progressionsThere is a thing called the three chord theory. Here is the just of how it works.You take a scale say the key of C major and assign each note in it a number.you then take the notes that fall under the numbers 1,4 and 5 . Those are the primary chords for that key. So as you can see by the chart on this page the three primary chords in the key of C major are C,F and G they can be major minor or seventh chords.What ever works for what you are doing. These three chords in any key are used in just about every chord progression. There are tons of songs that use only these three chords.So if you are trying to figure out a song by listening to it and you can nail one chord you could count up from it to the 4 and 5 chord and maybe just maybe those will be the other two chords.
moreMore chord progressions
There are more chords that can be
included. They are called the secondary chords
.they are the 2, 3 and six of the scale
you are playing in. In the chart above that would be the D,E and F these
are all usually minors but can be major or seventh