Ride slower!!
I'm serious. Slow down and focus.
What do you have to do to ride a bike?
Pedal
Change gear
Brake
Accelerate
Maintain speed
Change hand positions
Corner
Focus on making each operation perfect. You can only do this by slowing down to give yourself chance to do everything perfectly.
Keep your cadence between 90and 100rpm at all times, including accelerating from stationary.
Let up slightly and only shift when your feet are in the 6oclock-12oclok. So that each gear snicks into place perfectly.
Work on your progressive braking. Apply the front gently and squeeze on the power, dab a little rear brake, gently reduce the brake power as you reach the speed you want.
Make hand position changes frequently, and with as little impact on the stablity of the bike as possible. Move one hand then the other.
Cornering, make yourself aware of countersteering. Crouch down and use pressure on the inside bar to smooth your cornering line, when you are going very fast use your inside knee to make fine tuning to your line. Stick it out to widen your line, pull it in to tighten your line.
Practice manovering at slow speed. How slowly can you ride? Practice u-turns aand picking things up off the ground without unclipping.