Countless songs we all know and love are built around many of the same harmonic changes.
There's nothing wrong with that. You can't copyright a chord progression. In fact, 99 (or so) percent of all Western chord progressions can be traced to either tonic-dominant (I V) or tonic-subdominant (I IV). Everything else is generally some sort of substitution.
Using a well-known chord progression can create an instant sense of familiarity with your listeners. Even those who don’t consider themselves musical can, to a degree, predict where a melody is going if it's presented over a set of chords that has been ingrained in them. That increases the chances of them humming along.
On the other hand, straying from the predictable can also make your music memorable. I'm a big fan of progressions that step outside of conventional lines. But remember: if anything goes too far over your audience's heads, they're likely to tune your music out (raise your hand if you've ever had to watch someone else to know when to clap at a jazz club!). Know the audience you're writing for and give them what they're willing to handle.
Here are a few simplified strategies to give your harmonic progressions a little extra color.
1. Use functional substitution
Sounds fancy, right? Basically, every chord within a key serves a particular harmonic function: tonic, subdominant, or dominant. If a chord shares the same function as another chord, they can often be swapped for each other. Try substituting VI- or III- for I. Same with IV for II-. For a characteristically unique sound, try VII diminished for V.
This idea is called "Diatonic Substitution," and it works fantastic for adding more harmonic range to any composition. Learn more about this principle by watching my lesson on it.
2. Elaborate a little
Triads and power chords are great. I'm a huge fan of both, and honestly, I don't use either nearly enough in my own writing. Maybe that's because tensions are also very cool and can be created with simple ideas like; suspended chords, altered chords or even with extensions, (7th, 9th, 11th, 13th).
Of course, there are some serious rules about chord building, (but that's a whole other article), so throw those out the window for now, and just try adding other notes that are diatonic to the key into your voicings. Seventh chords are a great place to start. Convert a few Major or Minor triads into "Major 7th," or "Minor 7th." Try adding in a "Dominant 7th," as well. You could also try simple "add" chord ideas like the "add2" and the "add4." Check out last week's Blogger post, "How to Play Guitar Like James Taylor," for a number of these extended chord concepts.
When in doubt, overall, just follow the simple rule of, "If something sounds bad, don't use it!" Generally speaking, adding in notes that are a half step away from other notes in the chord will lead to something ill-advised, though not necessarily un-useable.
3. Pedal something
I'm about to give away a pretty big secret, so lean in: some of the most "complex" progressions that you could ever use may have actually started out with one of the easiest types of harmonic experimentation's ever. And, it is referred to as "Pedal Tones."
Pick a note or two. Then, try every other note (all 12 options) under that first tone in the bass. If you want to get heady and analyze everything as it happens, go for it. For instance, this can sound pretty cool when a seventh becomes a third or when anything becomes an eleventh just by moving the bass note.This can sound particularly awesome. Especially if done with open strings in alternate tunings and using a capo!
Fair warning: this method can force your hand a little melodically because things can get pretty chromatic. When first using this strategy, try to write more simply. Perhaps try and stick to those common tones that are more diatonic. Over time you'll hear more complex movements, nd be able to better control them.
If any of this went over your head, you should start making a study of the basics of Music Theory and Harmony. My "Music Theory Course Material," includes a lot of good foundation info on diatonic harmony, musical form, key centers and other good stuff.