Mario Kart 64

Speed Burst:
As soon as the light turns blue, press the gas button to get a nice turbo boost.
Be careful, however, as you will spin out if you press it too soon.

Mirrored Tracks:
After getting a gold medal on 150CC you will be shown the credits.
After reseting your machine, the title screen will have changed,
and you will be presented with the option of racing Mirrored Tracks.
The tracks will not be raced backwards,
but instead the turns will be opposite and you will still be going in the same direction.

Ghost Races:
Programmed into Mario Kart 64 are "ghosts" for three different raceways.
You should all be familiar with the option of saving your "ghost" onto the N64 Controller Pak...these are the same. These "ghosts" represent NCL's best Time Trial races, and once accessed, can be raced against again and again!
In Time Trial Mode, select your player and choose one of these courses:

Mario Raceway - 1:52
Luigi Raceway - 1:30
Royal Raceway - 2:40

Simply beat the above mentioned times (well, okay, it's not that easy!),
and then immedietely choose to retry that course.
When you begin, it should say "NOW, RACE AGAINST THE COURSE GHOST!!!,"
and you will be racing against one of the "ghosts." On Mario Raceway, you will race a ghost of Mario.
On Luigi Raceway, you will race Luigi, and on the Royal Raceway you will race Peach.
These "ghosts" follow the same course everytime, and are an excellent way to practice.
After accessed once, you can still race against them after you turn the power off.
Simply choose Time Trials, and choose that course.