Braking
Tap the "Brake" button when needed, such as when a row of crystals is approaching. This allows you to make sharper turns to collect all of the crystals. However, do not overuse the brakes or it will affect your completion time. Additionally, if you slow down too much, you may stop moving especially if there is an incline, which will end the level.
Gaining speed
If the tube is completely covered, you can move wherever desired on the slide. To build up speed quickly, remain on the portion of the slide where the water is flowing to increases your acceleration.