Abusing a glitch in the game. Pushing both A+B buttons where the track changes angles will fling you into the air. I made use of this several times in the run, specifically: (youtube time, not game time) 0:08, 0:53, 1:01, 1:09, 1:23, 1:32, 1:38, 1:49, 1:54.
I don't remember what my best non-assisted score was... It was in the 1400s at least. That was back in the day when I was a kid with infinite patience