You can use a mushroom to drive through the waterfall by Yoshi's arms.
After the top hump, you can hop over the grass section to skip the turn.
On the last hump, you can drift through the tires like on GBA Mario Circuit.
On the final two turns, you can use power items to boost over the grass.
Strategies
Yoshi Circuit is a good bagging track due to the usefulness of power items.
Power items can be used after the second set to get through the grass by the Piranhas. Alternatively, there's an extension area for Bullet Bills after the second set, so you can bill by the nose or even the waterfall.
Bob-ombs can effectively trap people at the start of the tunnel, the turn before the third set, and the final S turn.
