Watch the Interval Shapes online guitar lesson by Jennifer Batten from Rock Sauce for Rhythm Guitar
Memorizing the shapes of intervals is a worthwhile effort. Once you do, you’ll be able to quickly decipher the chord tones in chords you already know, and be able to easily add extensions or alterations to them. If you don’t already know how to play a chord you see on a chart, you can create it visually by knowing 1) its ingredients i.e. root, minor or major 3rd, 5th, minor or major 7th and 2) combining the interval shapes you need. In this video segment I play random intervals and then say what they are. To quiz yourself, hit pause as soon as I play a new interval so you can come up with the answer.