Two different approaches to getting off your plateau are presented by Steph Davis and dailyclimbingtips.com. Steph says in part:
“My advice is to mix up what you are doing. One thing that is guaranteed to improve your climbing is to devote some serious attention to core (stomach) workouts and to hip opening flexibility. For a month or two, cut back on your gym climbing and replace that with ab workouts (of your choice) and hip opener stretches.”
Tristan, at “Daily” has a 5 step program including doing pyramids.