1. Press and hold R and the joystick while turning. (Left or Right it doesn't
matter)
2. Behind the car dust should be coming out in the form of a V then it will
change to a gray E.
3. (If turning left) Click the control stick right then back left. The E's
should now turn yellow.
4. Repeat and the E's should turn red.
5. Release R and you car will get a burst of speed.
6. Note the moving of the stick changes how hard your car is turning, keep you
car in control
7. Try this trick on Rainbow Road, you can do it three or four times in one
turn. (This is essential for beating the computer in the harder levels)

--from GrahamBCP

Shortcut in royal raceway

When you off the big self prepelled ramp take asharp left and if you make it you will be right by the finish lineif you don`t make it you`ll run into the mountain or you`ll just miss.
This

Ghost Rider: Luigi

Go to the Luigi Circuit and race the course under 1 minute and 52 seconds (1:51). If you're able to do it you can then race against your ghost, "a recording of the course's best time." What's even better is that the ghost is permanently saved into the game.

Ghost Rider: Mario Raceway

Like all of the courses, Mario Raceway has a ghost to race against in Time Trials.

Try to beat this time: 1'30"00 to get the ghost to appear.

After you beat the above times, immediately RETRY and you will see the message "Now Meet the Course Ghost."

Ghost Rider: Royal Raceway

Go to the Royal Raceway and race the course under 2 minutes and 40 seconds (2:40.00). If you're able to do it you can then race against your ghost, "a recording of the course's best time." What's even better is that the ghost is permanently saved into the game.

Essential Short-cuts

There are many short cuts in Mario Kart 64, most of which are easy to see and to execute. But even the most obvious ones are easily overseen, and N64.com has organized them into a short, quick reference guide for Mario Kart fans to access. We realize many short cuts have not been listed here, but we believe these are the real key shavers designed to clip off a few seconds, putting you ahead of your rivals in any mode.

1. Noku Noku Beach: The waterfall: Many people believe this is only accessible with a mushroom power-up, but this is false. Gamers can make the jump off the ramp without a power-up. Just aim straight into the cave, use jump (the right shoulder button) make sure not to hit the walls, and jump right out from under the waterfall.

2. Hydro Pond (the ghost house): After driving through about half the course, your driver will enter the ghost house. Upon entering, take a right, but not as sharp as normal, and you'll pass by a wall on your left. Instead of aiming toward the bats, you'll aim slightly left and pass on the left side of the wooden pole. This might look like suicide, but jump over the edge of the star-shaped pool and you'll pass up that first-place player.

3. Rainbow Road: Right at the start of the race there is a large hill from which each racer makes a slight jump. Oftentimes if you're aiming too far left or right your racer will fly off the course, which is not a short-cut. Here's the deal: just as the slope begins to descend, press jump and you'll fly much higher and farther than ever. This shaves seconds, and in the second and third laps, your racer should jump right over the heads of those difficult-to-see Chomps.

4. Yoshi Valley: This course is a tangle, as shown in the introductory map, but here are a few short cuts that will enable you to beat just about anybody. Follow the course until you hit the mazey part. Immediately go left and stay left. The first part of the short-cut is to stay left and on the narrow part of the course.

After managing to do that, you'll hit a little checkered ledge, and you'll see a big red and white sign on the left pointing right. This is the hard part. Accelerate as fast as possible and stay to the far right. As soon as the rail on the left side ends pull a hard left powerslide off the road. You'll continue the powerslide onto the upcoming road after you land, and if you do it right, you'll have shaved off at least 10 seconds or lead the pack. Of course, this one takes a lot of practice, but once mastered, it can't be beat.

5. Donkey Jungle Park: Near the beginning of the race is a self-propelling ramp which sends your racer across a giant river. This one is quite simple. Instead of jumping straight off it, aim to the far left and you'll be ahead of the crowd by a few seconds. It works.

Second, this course is full of sharp turns. Use the mushroom power-ups as you pass across the jungle terrain and though you'll be hit by coconuts, you'll still end up farther ahead than if you didn't.

Third, there is one cave on this course that disrupts many players because of its weird angles and hard-to-follow path. But look at the ground and there is a light-colored path, which makes it far easier to follow.

Fourth, upon entering the cave, accelerate to the maximum and aim toward the steep slope. If your racer is going fast enough then pull a hard left powerslide and you'll slide right up the slope, thereby shaving a few seconds.

There are more, but they have been listed separately, so don't forget to check them out!(like Wario Stadium and Rainbow Ride)

Big Rainbow ShortCut

Here's a massive, risky shortcut that'll absolutely blow the socks off anyone who challenges you to a game of Mario Kart 64.

Go to the Rainbow Ride Course, and at the start, before you get air on the big, long hill, take a wide turn left off the course and into midair. If you've got the correct angle and speed (which will take some practice), you'll fly through the air for nearly 10 seconds, and will land on the same course below with a sizeable bounce. While you're in mid-air pull your hand off the accleration and hit the brakes because when you land your speed will cause you to bounce right off the course.

If all goes well, you'll be so far ahead of everyone else the rest of the race should be a breeze (that is unless the cheating AI kicks in...).

Wario Stadium Shortcut

On Wario Stadium, as soon as you start you'll go over four jumps. On the third jump start moving to the left hand wall of the forth jump, so that you are perpendicular to the wall. At the top of the jump, use the R button and jump the wall. This may take a while to master, but it is worth the practice. (Don't worry if you fail on your first attempt, try again because your opponents will not get to the landing point of the short-cut for at least half the race).

Yoshis Highway Shortcut

When the course starts getting mazy go right, then go left at junction, then make sharp right(across Bridge),then follow arrow on mountain.
This

Banana Trick

When you hit a bannana peel put on your brakes immediately. This will prevent you from skidding out. After you brake for 1 second release and give her the gas. This is really helpful in Battle Mode because you will not LOSE A BALOON.

Passing Trick

When driving, if you can get directly behind a racer for a short time, you'll see air come off of both sides of your kart (like when you go off a ramp), and you'll get a short outburst of speed, not much, but enough to pass whomever is in front of you.

Ride in Reverse

To race any course in reverse you must earn a gold cup in all of the 50cc, 100cc and 150cc races. You'll know you've succeeded when the title screen changes.

Lightning Fast Start

Start a race and watch the lights carefully. Press A as soon as the second light dims. If your timing is right you'll get a turbo boost that'll leave your opponents eating your dust!

D.K. Parkway Hint

At the beginning turn around and go into the cave. About halfway inside turn around and just before you leave the cave turn a sharp left.  You should fall down a black whole, you will the be picked up by clowdy and put onto the course somewhere else.  If its in the cave you can go and pass the finish line and turn around and do it again.  If it doesn't then keep practicing
This

All New Tracks

If you beat the game in 150cc and you come in first every time,  after you restart the game there will be a whole new begining and there will be new tracks.

Bowser's Castle Glitch

This code takes practice and precision.  I noticed this when I was bored with the game.
- BOWSER'S CASTLE -
When the race starts, go in reverse around the corner and fall into the lava.  You will be put on the "island" with the item boxes.  Try to get shells or a blue shell and again, go in reverse.  You will be put by the loop.  Go the correct way, and stay to the right, and stop where the course begins to straighten out and stop there.(the last little bend on the wall to the right) before the drop to the island.  Now hold the shell and wait for the other karts to drive by.  If you were in the right spot, the other karts will hit your shell and go over the wall and land back at the bottom of the loop.  Instead of going foreward, they think they need to go straight and instead, they bounce off the wall.  You can drive by and watch without coming in 8th place.

Different Award Ceremony

This is a trick (sort of)  that I only recently found out about, even though I've owned the game for some time. In the one player grand prix, the difficulty doesn't matter but it's easier to do in 50cc, all you have to do is get 4th. It can get tricky because the racers won't always rank in the same order every race. After getting fourth, the awards ceremony will take place. The three winneres will go to the castle and you will stay behind. As you drive away a bomb will follow you and blow you away. Try it!

See the Princess' Castle

In the Royal Raceway circuit, right after land from falling off the ramp, stay to the right, and you will see a pathway. Follow it, and you will be in front of the castle. Although this only wastes time, it's just a nice thing to see.

Game Glitches

1. Luigi,(need two or more players.) First pass a lap and get the itembox from the hot air balloon. Then go to the finish line. Then line up with the white line by the mountain. The person with spiny shell hold it. The other person goes to the opposite side of the track then charge at the spiny shell. You will fly through the mountain and land in the bridge.

2. Toads turnpike.Must have 2 players. First one gets shield power.Then go to intersection on track. Plyers get on opposite sides of the track. The person with the shield power turns it on. The other person charges at the person with the shield power. He then goes through the wall and on to the track. He lands inside a tunnell. This counts as a lap.

3.Royal Raceway.(Not use heavy people) In expert mode Race untill you are at the ramp when you hit the boooster make a hard left.Not to hard or you will go in the moat. When you hit mountain side, hold control stick up, hold 'A' button, and rapidly press 'R'. and you are on the mountain ledge.

4. Put out many fake itemboxs, and a few will be invisible.(You can Still blow up when you hit the invisible prize box.)