The fundamental approach to master any technique is simply too slow it down until you can play it accurately, then you incrementally increase the speed each practice session. The speed should never be the primary goal. The focus should always always be correct and accurate execution. The speed will just take care of itself.
Failure to execute at speed comes from an underlying lack of awareness of what our body is doing, we have to train our "6th sense" of proprioception. Focusing only on hitting a targeted speed distracts us from observing our body and really physically sensing what the accurate technique requires in terms of movement. When we slow down and don't stress out on hitting the target speed, we can spare the attention needed to understand and train the mechanics of our body better.
Failure to execute at speed comes from an underlying lack of awareness of what our body is doing, we have to train our "6th sense" of proprioception. Focusing only on hitting a targeted speed distracts us from observing our body and really physically sensing what the accurate technique requires in terms of movement. When we slow down and don't stress out on hitting the target speed, we can spare the attention needed to understand and train the mechanics of our body better.