+1 about delaying a downshift in a braking zone.
Try sitting with the car parked, with your foot on the brake, and blipping the throttle to get the right idea. I usually have my right knee pass under the steering wheel and to the left side to get a proper blip.
Once you get the parked and revving figured out, then get to a hill and practice getting up the hill with the foot on the brake and revving. (this is harder in our fancy cars with hill assist).
Then when you're ready to try to incorporate downshifting, focus more on revving the car and balancing your foot between the brake and throttle to find the right RPM's. A cloverleaf works perfect for this.
Once you're good at that, then you work on kicking/blipping the throttle.
You're starting at the final level of learning....you'll get it!