re: In need of advice.

The chord changes are really fast on that song. Learn to play from G to C by just moving the 2 fingers on the E and A strings while playing G down to the A and D strings while leaving the pinky and ring finger parked on the B and high E strings. You can also play the D7 by moving just the index finger to the G string and leaving the pinky and index parked. Em can be played by moving the index and middle fingers to the A and D strings the normal em formation while keeping the pinky and ring fingers parked. You can change chords really fast by doing it this way.

Here is the G chord.