Another common rhythm guitar technique in R&B is to play a staccato chord on the backbeat along with the snare drum. This helps to create a tighter band sound. Sometimes the guitar plays on both the second and fourth beats, other times on the second beat only.
Here is a new seventh chord shape which is useful in a variety of Blues styles. Be sure to damp out the first and fifth strings with the left hand.
In this example, the guitar slides into the first beat to give the rhythm some forward motion and drive. Instead of playing with the snare drum, the guitar is linking with the bass drum and leaving space for the other instruments in the rest of the bar.