Just before the last turn the player can go in the sand and do trick off the ramp.
Skip the last trun by going through the sand.

Short cuts

Luigi circuit

Moo moo meadows

Cut through the grass at the beginning
Use a bullet bill in the left grass at the beginning to use a secret bullet bill path

Mushroom Gorge

Just before the part with mud you can use a mushroom to hop over the lake by launcing off the bumps

•At the beginning trick on the mushrooms to the left
•Cut through the grass at the last turn

Toad's Factory

When approaching the Chain Chomp, use a mushroom to boost towards a ramp in the sand.

Mario Circuit

After going up the first set of elevators, boost through a shop on the right of the mall.
Mushroom off of the indoor fountain before the second set of elevators to launch over them.

Coconut Mall