A few tips picked up from various people/sources over the years..
1. pull brake lever with pads of your index/middle finger--allows you to blip the throttle without accidently jerking the brake lever, smooooth
2. if you’re not braking, aka, just dumping down a few gears for a long pull, “slowing down a tidge”, dab your rear brake for anyone behind you. I’ve ****** off people before when rev-match-downshifting in the middle of long corners on group rides, I ride at the back/shotgun now. They don’t expect it, because they can’t do it smoothly.
3. “Preload” by putting a bit of pressure on your shifter—will shift effortlessly the moment you pull the clutch past the slack and through the bite point. Similar to clutchless shifting.
It’s all about the timing
Personally, I don’t dump more than 1 gear so that I get the “joy” of doing the process a few more times. Obviously this is not a 600/liter bike, and I get a lot more practice using more gears.