Watch the Day 8 online guitar lesson by Ravi from Learn Guitar in 21 Days

Because the I-IV-V does open up so many songs, today we're still going to focus on three chord songs, but I also want you to go back and review the two-chord songs that you played before.

It's always important to build your repertoire, not just learn songs and then trade them in for new ones. Try sneaking in a little rock/blues rhythm, as that will really help capture the feel of many of those tunes.