A Simple Song Arrangement Principle
While arranging songs, a common principle that works almost all the time is:
2 instruments should not be playing the same thing at the same time.
For instance, if there are 2 acoustic guitars playing E-C#m-A-B, one guitarist can play the usual open chord shapes, while the other can clip on a capo at the 2nd fret and play the same chords in the D shape (D-Bm-G-A). Another alternative is to put the capo at the 7th fret and play in the A shape (A-F#m-D-E). Though the chords played by both the guitars are the same, the difference in voicing creates a better overall sound without stepping into each other's musical space.
Yet another creative method to get a different chord voicing is to use what is called a cut capo or partial capo or Foote capo (in honor of Billy Jean Foote who is credited to have used it first). A regular capo covers all the 6 strings while a cut capo covers only 3 strings i.e. the 5th, 4th, and 3rd strings (A, D, G) on the guitar.
To understand the cut capo, you need to understand how the drop-D alternative tuning works. Typically, each string of the guitar is tuned to 6 notes. Starting from the 6th string, the notes for the standard tuning are E-A-D-G-B-E. In drop-D, the strings are tuned to D-A-D-G-A-D instead.
Yes it means you have to relearn chords shapes, but the resultant voicing variations are worth the effort, trust me! A classic worship song example is Casey Corum's "Dwell", which is played on DADGAD tuning with a capo on the 5th fret. The whole song runs on a repetitive G-Dm7-C progression using the following chord shapes:
Take some time out to practise "Dwell" to get a feel of DADGAD tuning.
Basic Chord Shapes in D-A-D-G-A-D Tuning
Now let's get to learning some common chords used in contemporary worship songs in DADGAD tuning. If you strum all 6 strings without holding down any fret, you get a Dsus4 chord. Then you can try out these shapes:
Now bring out your Cut-Capo!
If you've got the hang of the above shapes, you are ready to use a cut capo. Re-tune your guitar back to the standard E-A-D-G-B-E tuning and place the cut capo on the 2nd fret. This causes the strings to sound these notes: E-B-E-A-B-E, which is DADGAD modulated to the key of E. Refer this picture for better understanding:
Now if you play all the shapes in the above chart, you will be playing the same chords, but in the key of E. So D=E, Em=F#m, D/F#=E/G# and so on.
To play chords in the key of F using the same shapes, move the cut capo to the 3rd fret and place a standard capo on the 1st fret like this:
To learn more chord shapes, simply search for drop-D chord charts, there are many available all over the Internet!