Looking up Terms
Put this into Google (or Bing) and see what you get:
flow chart chord progression
OK, maybe a bit overwhelming, and probably "all Greek" to many of you, but this kind of chart always gets me going in deeper. If you are somewhat visually oriented, a few of these charts may be a kind of "jumping-off point" for you in exploring how one chord leads to another.
When i tried "cycle of 4ths chord progressions" I got this:
Pretty cool stuff here, and what I usually do (not having a piano or guitar in from of me most of the time), is to try a little bit of this stuff on the dulcimer in my own esoteric way. For instance, if I'm in DAD, I might start the cycle on F# - not being so nit-picky about what kind of chord I'm playing (you can always just do a Root-5th-Root chord as a barre across the fingerboard: at fret 2 for the F#) - and going in 4ths until I get HOME to a D chord! Try it, you might have fun! (hint: the second chord in the cycle would be B or Bm)
Modal Chord Progressions
Getting more specific to the uniqueness of the mountain dulcimer, you might want to find out about this whole "modal" thing and what it means. If you typed in modal chord progressions to a search engine, you might find some interesting leads. As I've mentioned many times, Gary Ewer always has some of the best immediately USEFUL stuff anywhere:
AND....you can play many of these chords on your DAD-tuned dulcimer! The first part of it talks about regular old A Major (which you have completely on your DAD dulcimer thanks to the 6+) then shows you some B Dorian changes.
A Free Download
For today's giveaway, I'm offering a free download of one of my favorites from my Too dark to work... collection (look for the little down-pointing arrow below the waveform):
This is a mixolydian chord progression that is as circular as you get. I hope you enjoy it, and I hope you have some fun messing around with some of this modal stuff.