Watch the The I-IV-vi-V online guitar lesson by Ravi from Guitar Lab: 30 Rock & Pop Progressions

In order to add even more interest, instead of returning to the I in between, we can go to its relative minor, the vi. This maintains a similar sound, but adds a slightly darker flavor.

Examples: She Drives Me Crazy, Hit Me With Your Best Shot, More Than A Feeling, I Got A Feeling, Say