If you're still having issues with muffled notes, then isolate your problem, and try to come up with a solution. For example, if you notice that your Gmajor chord isn't ringing clearly, then play each string in the chord, one by one, noting which strings do not ring. Next, identify why the string isn't ringing. Are you not pressing the strings hard enough? Is one of your fretting fingers not curled enough, and is touching two strings? Is an unused finger lazily touching the fretboard? When you've isolated the probem(s), try to correct them, one by one. Chances are, the same problems are occurring whenever you play that chord. Divide, and conquer.


