I think I read on here somewhere, and I started doing it(works great)
pick 2 chords, and practice changing between them several times(I go 20), then throw in a third chord and basically start over.
I started with D chord to A, then G, D, A(and actually I had to practice D to A, then A to G, then G to D to complete the cycle).
What also helped me was I took a 3 chord song and played it over and over (the one I did was Country Boy Can Survive, which is the above chords).
Right now I'm playing Lynyrd Skynyrd's All I Can Do Is Write About It(which goes G to D to Em to C).
The biggest deal in all of this is to get a clean chord out of all of them through repetition. Hope that helps you
