Mute City I Practice Mode + Golden Fox as your rival for a double-bump opener. In the S-corner with the dirt, you can cut off the left patch of dirt by driving on the extremely thin line between the rail and the dirt . (Bianca City anyone?). Very hard to do but it will get a few tenths off the opening lap if you managed to limit your speed loss. On the next laps, stick close to the right rail, ignore the jump plate and use your boost when you get at the S-corner. You can now cross the two dirt sections in a straight line without losing speed. Approach the final hairpin from the left and cut it as close as you can with a blast turn without touching the inside dirt.
Big Blue Practice Mode + Golden Fox as your rival (you get the idea) All corners on this track are pretty easy and can be cleared with just a few taps on the accelerator. Always stick as close as possible to the rails while doing so. Again, boost in front of the dirt sections so you can drive over them and cut the corners a bit sharper without losing speed. If you're good enough , try cutting some rail as well to gain those final tenths of seconds.
Sand Ocean Practice mode + Golden Fox. Have the Fox hit you the first time on your right back side so it will catch up more quickly. It should give you the second bump just before the first right turn. Use a blast turn after the second bump to regain control and get through this corner. Stay in the center of the short zig-zag section and avoid the rails Approach the tricky hairpin that follows from the right and cut it as close as you can ( you may want to let go off the accelerator for half a sec ) On later laps, boost immediately after you've cleared it. Take the next right turn as tight as possible (try and cut the inside rail ) A short tap on the brake can come in handy here. The rest of the corners are easy enough to clear with just a few taps on the accelerator although the last one might give you some trouble if you're not on the ideal line. Avoid touching the rails here at all times !
Death Wind I Training Mode + Blue Falcon ( works better here than Golden Fox ). Pretty hard to get it to work: you have to swerve extremely left after the start and hope the Falcon will hit your right back side. It should then catch up again in between the dirt patches for that time-saving second bump. Hitting the 3 boost arrows on each lap is essential. Beware of the wind gusts which throw you off-line: compensate by steering a little bit into the direction of the gusts to keep straight. Avoid touching the rail after a boost arrow or your speed will drop back much faster than normal Boost past the start line in front of the first right dirt patch: that way you can stay very close to the right side going over the dirt and take the first corner very tight , even cutting the inside rail. Try and hug the other right corners as closely as possible.
Silence Training mode + Golden Fox. Have it hit you on the right side again the first time or it won't catch up quickly enough for a second bump. When the track splits, take the shorter left path between the mines but be very carefull that you don't miss the jump plate when turning left or you'll be forced to drive over the dirt. In the middle of the track you'll be faced with a very tricky hairpin: Steer sharply left into the first part with a well-timed blast turn, then switch to the right and rail bounce into the left rail as you exit the corner. Boost a few seconds after bouncing back on the short straight and speed towards the final hairpin-section. The best way to get through here is to entirely let go off the accelerator . With the accelerator off you can easily guide the Stingray through the corner and there's no need for rail bouncing. Press the accelerator again once you've cleared the hairpin: the boost should still be active for a few seconds and put you back at max speed, ready for the next lap.