One thing to do is, stop actually playing, from time to time.

Another is play up the neck inversions, for a change - rests your fingers too, because you are using different muscles. And with some of those up the neck inversions you can get a good effect by leaving open the strings that guve you notes that into the chord you are playing. Going up the neck doesn't necessarily mean playing barre chords.

I quite agree with greg about being pretty sparing with the relative minors and the 7ths and so forth. I think it almost always sounds better in folk music if stuff like that is rationed. It's a matter of personal taste though.