Some things are only revealed through experimentation. That's what I've learned in work, play, art, life, you name it. Composing a guitar instrumental is no exception. Any songwriter will tell you that a conventional approach will most likely yield conventional results, that's why I've always encouraged a bold, freeform and more risky approach to writing and playing. No risk, no rewards.
Exploring new ways of looking at your instrument can help you discover new ways of writing stronger and more original material. It is my belief that no amount of writing based in theory or conservatory training can ever substitute an inspired, original tune written in freeform. We've all heard an innovative guitar song before and thought "Now that's different!" Well, these songs didn't fall from the sky. Fortunately, someone pushed the envelope a little further.
Something I like to encourage while writing material on the guitar are happy accidents. You know, those unusual musical moments when you go, "Wow, how did I do that?" or, "What the #@% was that, and how can I do it again?" I try to encourage these "accidents" as much as possible because most of my material comes into fruition this way. For instance, a standard picking style applied to an alternate tuning (discussed below) can stir up some interesting results, and so can experimenting with freeform chord changes. A major 7 chord within a blues triad? Well, you don't know until you try. Explore the possibilities.
Alternate tunings can play a significant role in writing fresh material. In fact, if the tuning is unusual enough, it's as if you are playing a whole new instrument, giving you a fresh perspective on writing that you wouldn't have considered otherwise. An alternate tuning compels you to pick and chord differently, and in a way, forces you to look at new possibilities of your playing style. Popular tunings like "Drop D" and Open tunings are genre standards in their own right but I've listed a few others below you may want to explore:
Standard: E A D G B E
Open C: C G C G C E
Open D: D A D F# A D
Open G: D G D G B D
Open E: E B E A B E
Drop D1: D A D G B E
Drop D2: D A D G B D
D Modal1: D A D G A D
D Modal2: D A D D A D
Big City: D A D F# A A
D Minor: D A D F A D
G Minor: D G D G Bb D
Baritone: B E A D F# B
Baritone: A D G C E A
Old Spanish: D G D G A E
Personally I find that the open G is the most rewarding tuning for me but if you can't find one you like, make one up! It's a free country. But seriously, alternate tunings are definitely worth investigating and turning those keys can be time well spent.
Also, it's important to remember that a mediocre song doesn't have to remain that way. If you have written previous material that you're not exactly proud of, try incorporating a bolder chord progression to "break up" the song and keep it interesting. Getting the listener's attention and keeping it is the whole idea and if it gets your attention, chances are it will get their attention. Gain inspiration from all sources of music, not just your genre but all varieties. Don't limit yourself.
Harmonic tapping and sweet notes, on-the-fly tuning, and tapping out percussion on the guitar body are all popular ways of enhancing your sound. These methods are being perfected each day by such innovative artists as Adrian Legg and Preston Reed, but finding what works best for you should be at the forefront of your search and discovery. The methods are there for you to find... so why not have fun trying?
Bryon Thompson's regard for creative and unique instrumental guitar music has led to producing three solo recording projects totaling 30 original tracks.
His latest instrumental CD is entitled "Get On With It".