Most chord formations are closely related to the five basic major chord shapes (shown in the following diagrams). To remember the 5 shapes, think of the word caged.
C
A
G
E
D
Practice changing between all of these shapes – C to A, C to G, C to E, C to G, A to E, D to G etc, slowly with your metronome until you have them memorized and can instantly move from one chord to any other chord.
Once you can remember the shapes for the chords, try the following progressions.
Where common notes occur between chords (e.g., 2nd finger in C chord and A chord–as in the following example), keep the finger down when changing. This is called a pivot finger. It will result in a smoother sound.
Another important aspect of left hand technique is the use of guide fingers. This involves keeping your finger on a string and sliding it to a new position on that string when changing chords.
For example, when changing from a D chord to an A chord, keep your 3rd finger on the 2nd string and slide it back from the 3rd fret to the 2nd fret. Like the pivot finger technique, the use of guide fingers helps to create smoother sounding chord changes. The following example makes use of guide fingers between all three chords.
This example uses both pivot and guide fingers and contains all the shapes you have learned.