Practice in grand prix mode, for a start. Or just use the practice mode. With 29 CPU players. On master difficulty. (Complete all the cups in GP mode in expert)
For Captain Falcon trains, try to get as many capsules in one lap without slowing down or stopping; in V. hard mode, I managed it by collecting 2/3 capsules per lap. Make sure you never have a split in between a group of capules on the final lap. Use the default speed/acceleration setting.
In save Jody, you need to act fast. Continuously boost, don't even think about slowing down. You'll find the drifting (R and L triggers) the most useful. Use 50% speed setting, or set it to the maximum. You'll get a little less of a boost at max. speed, but a high acceleration isn't recommended. There comes a point where you will run out of boost power, and hardly any/no capsules are around.
I beat this with less than a second left. Good luck.
Note: You have no hope in hell of winning if you hit a wall in V. hard mode.
It's worth it. Beat V. Hard mode in story mode, and each chapter will unlock a new racer to buy. Hard mode gives you new pieces, and I'm pretty sure new tracks, too. I can't remember.
How 'bout we add a little more to the topic: What custom ships do you use, if any?
I use "Bright Goose Z"; C body, A boost, C grip. 1690Kg, medium load.
It uses Aqua Goose for the body, Bright spear for the cockpit, and Triple-Z for the booster. Slightly weak turning, great for drifting, low accleration, great boost and whoahmgwtflol speed.
I'm addicted to this game, and use my Wii primarily to play it. :E