One quick way to add pedals to your progressions is to bring in some droning open strings. Many great guitarists have used this sound, including Alex Lifeson, Randy Rhoads, and Steve Morse, all of whom influenced me directly in this approach. The arpeggiated 8-bar phrase below, one section of the song “Glasgow Kiss” from my new solo album Suspended Animation [johnpetrucci.com], achieves the sound I’m talking about. The shapes I’m fretting are mostly just plain old root-5-octave power chord voicings, but when you throw in the ringing B and high-E strings, the progression comes alive. Suddenly, rich sounding 4s (which you can also thinking of as 11s), 9s, and other pleasing drone tones fill the air. Add a touch of stereo chorus and it really sounds beautiful.
There are many ways to make chords sound richer. One thing I like to do is mess up ordinary chords a bit by adding different tensions and extensions. A lot of times, a simple chord progression can be made more magical through the use of pedal tones—ringing or repeated notes that appear within more than one chord successively. These chimey, recurring notes sound wonderful on any guitar, acoustic or electric.