Mini-Turbo
              To do a boost without a mushroom, press and hold the R (top right) and move the control stick in the direction of the turn. Move the control stick left and right until the smoke turns red/orange. Release the buttons and you will boost.

        Speed Boost
            Hit the gas and hold it between the second and last light and you will get an extra boost.

            There are also a lot of shortcuts in the game but i don't have them listed.