Watch the Basic Country Forms online guitar lesson by Jason Loughlin from Country Guitar Survival Guide: Rhythm
Let's talk about some of the country music forms. We use letters to describe sections of music. For example a verse of a song might be called an A section and chorus might be called the B section. One of the more popular is the A A B A form. This form can be found in jazz and American popular songs. It's typically a thirty two bar form. The B section is also called the middle eight. You may think of it as the bridge. Bluegrass forms may look like A A B B or A B. We also see variations on a 12 bar blues form. Most country tune are very simple harmonically drawing from the I, IV, V in a key. Typically, your first A section will end with a V chord to bring you back to another A section. The second A section will end with a dominant I chord to lead you into the B section. B sections start on a the IV chord mostly and end on V to set up the last A section. Thousands of great songs have been written to this form with little variation. Try analyzing your favorite tunes and see what you find. I think you'll be surprised how many of the follow the same form. There is a common substitution that finds it's way into many country tunes and that's called the secondary dominant. This achieved by treating any chord as a tonic and playing the dominant chord that leads into it. We do this to prolong the tension before resolving to the tonic and it also takes us out of key for a moment which could be a breath of fresh air or the lift a tune needs to keep it propelling forward. If we stack secondary dominants we create something called a cycle. A tune like Cannonball Rag is a good example of this. This works for any chord but the I chord since the dominant of the I chord can already be found in the key. It's most commonly found before the V chord.