I always thought my shifting was not not so good, not so smooth, I always try to ride the clutch a little shift to shift to smooth it out. until I test drove some hardcore super car with sequential gearbox like the F360 F1, Lambo SL E-gear... when I floored the throttle and hit the next gear, I thought I was hit by another car! I realized I was way to annal about how smooth I shift. just do it, clutch in, clutch out, just do it.
the weight of the fly wheel also affect shifting, rpm drops a lot quicker with lighter flywheel therefore you need to move a lot faster.