The G family of chords is related to the A and D families, so if you can already strum the basic chords in the A and D family, you're already halfway to understanding the G family. The basic chords that make up the G family are G, Am, C, D, and Em. Listen to “You’ve Got a Friend,” as played by James Taylor, to hear the sound of a song that uses G-family chords.
If you already know the basic chords of the A and D families, you need to learn only two more chords to get the G family: Am and C. The following figure shows the fingerings for these two new chords. Notice that the fingering of these two chords is similar: Each has finger 1 on the 2nd string, first fret, and finger 2 on the 4th string, second fret. (Only finger 3 must change — adding or removing it — in switching between these two chords.)
In moving between these chords, keep these first two fingers in place on the strings. Switching chords is always easier if you don’t need to move all your fingers to new positions. The notes that different chords share are known as common tones. Notice the X over the 6th string in each of these chords. Don’t play that string while strumming either C or Am.
To finger chords, use the “ball” of your fingertip, placing it just behind the fret (on the side toward the tuning pegs). Arch your fingers so that the fingertips fall perpendicular to the neck. Make sure that your left-hand fingernails are short so that they don’t prevent you from pressing the strings all the way down to the fingerboard.
The following figure shows a simple chord progression that you can play by using G-family chords. Play this progression over and over to accustom yourself to switching chords and to build up those left-hand calluses. It does get easier after a while!
Notice that, in each measure, you play beats 2 and 3 as “down-up” strums.
Knowing the basic open chords in the G family (G, Am, C, D, and Em) enables you to play a song in the key of G right now. Why not try your hand playing “Auld Lang Syne”?