E7-shape Chord
The main dominant seventh shape with a root on the sixth string.
Dominant seventh chords add a little tension to a chord progression, creating a desire for movement. The E-shape dominant seventh chord ("E7" for short) adds a minor seventh interval to the E-shape major triad.
The core E7 shape
This shape is commonly played as a barre chord, fingered 131211. Sometimes it can be a little challenging to get the ♭7 to ring out, but it's important, because that's the main feature of this chord.
Alternate E7 grips
Pinkie stretch
Another common grip is to add the higher-pitched ♭7 with the little finger, 131241. An advantage of this grip is that we're not so dependent on pressing the barre perfectly on the fourth string.
Drop 3 voicing
This E7-shape grip comes from the jazz world. It's convenient and comfortable, after a bit of practice. It's known as a "drop 3 voicing". The fingering is 1x243x. Mute the fifth string by leaning over a bit with the first finger, and/or touching it with the side of the second finger. Mute the first string by leaning over with the third finger.
Study and practice
Learn the chord grips
Master the E7 chord grips using the exercises described in How To Master New Chord Grips.
Alternate between major and dominant seventh
Practice switching between the E-shape major and dominant seventh chords.
V7-I cadence
Practice switching between the E-shape V7 and I chords of a key. This is a very common chord change, known as a perfect cadence.
(Tip: Change key in settings)