Hint :
Secret picture:
Hit the left wall in the tunnel in Germany to uncover a picture of a girl. Quick way to get in front of the pack:
(submitted by: MadHaTTeR)
Select a track with four lanes. When "Go" appears, steer to the two lanes that are open. Press A, A to do a couple wheelies and speed up. When you get to the first turn you should at least be in fourth place. If you have not hit anything, you could be in first place.

Dirty windshield:
Select New Mexico or Kenya as a track, start a race, then change the view to be in the car. Large insects will fall and splat on your windshield.

Moon track:
Successfully complete the game on "Cruise The World" mode under the easy difficulty level. An animation sequence showing your car being transported to the moon will be displayed. The bonus moon track may now be accessed after the credits.

Bonus tracks:
Successfully complete "Championship" mode under the master skill difficulty level. The Russia, Japan, and Florida bonus tracks may now be accessed.

Alternate colors:
Obtain at least 20 points in championship mode. Then, press L or R on the car selection screen.

Speed Demon car:
Obtain at least 9999 points in championship mode. The Speed Demon, with a 230 mph top speed, will now be available on the car selection screen.

Quick points:
Use this trick to collect up to 1200 points in ten minutes. First, enter the options screen and set the "Championship Difficulty" to "Pro" or "Master". Then, set the number of laps to one. Enter championship mode and select the expert tracks. Italy is the first track. After passing the checkpoint, repeatedly double-tap A until reaching the end of the tunnel. Continue on as normal until approximately one minute into the race. Then, use your boost to beat everyone and finish the race in first place. If you are under the "Pro" difficulty you will receive 40 points. If you are on the "Master" Difficulty you will get 150 points. After completing Italy the game will proceed to China. Pause game play and select "End Championship". Go to Italy again and repeat the process.

Two-tone colors:
Obtain at least 150 points in championship mode. Then, press L or R on the car selection screen.

Secret championship mode:
To get a secret championship mode successfully complete all 3 championship courses on beginner and pro levels.

Extra nitro in championship mode:
Start a race and repeatedly tap A (accelerate) to keep the RPM in the red area. Keep tapping until you start driving to get the effect of a nitro without using one. This will help your car get in first place immediately while saving nitros.

Auto accelerating:
(submitted by: Kim Holliday)
When you are in a race press A, pull the controller out of the N64 and you will still accelerating.

Power level 1:
Obtain at least 8 points in championship mode. Then, press C-Up or C-Down on the car selection screen.

Power level 3:
Obtain at least 100 points in championship mode. Then, press C-Up or C-Down on the car selection screen.

Power level 4:
Obtain at least 500 points in championship mode. Then, press C-Up or C-Down on the car selection screen.

Power level 5:
Obtain at least 1500 points in championship mode. Then, press C-Up or C-Down on the car selection screen.

Power level 6:
Successfully complete every course in first place in the Cruis'n World mode under the hardest difficulty setting. Then, press C-Up or C-Down on the car selection screen.

Shortcuts:

Hawaii:
A blue scenic overlook sign with red arrow cones will appear in Cruis'n World mode. The instant the sign comes into view, take a hard left onto the off-ramp. Some trick points are awarded by this secret, when doing stunts. Another way to get trick points, is to do a two wheelie slightly behind a car. If done correctly, your car can perform a flip.

Germany:
Just before the last ramp on course, steer left so your car is headed towards the left grassy area. A rock side wall on the left will appear. Steer just to the right of the wall. If done correctly, your car will automatically do a flip for more trick points. This trick is handy if you miss the jump.

Australia:
Watch carefully after the third set of Kangaroos, to see a dirt road to the left. The trail leads to a ramp, were your car will have enough room to earn a automatic mega-flip. This trail could also be used as a shortcut.

Mexico:
As you are approaching one of the turns with a temple on the right, drive towards it slightly, and go just left of it. Your car will crash through some breakable trees and other objects before hitting a jump.

Kenya:
Begin game play in cruise mode. Go to the left a short distance before the second check point. Stay to the left and go through the third check point. Follow the trail that is not too far ahead to find a ramp.

New York:
Begin game play in cruise mode. Find the off-ramp right after the third check point. Jump off the ramp to get some trick points. Note: Do not try to get on the bridge.

China:
Begin game play in cruise mode. Go to the left immediately after the first check point to find a trail. It will jump the road and continue straight until you are back on the track.

Bonus cars:
Begin game play in practice mode and select the "Practice Championship" option. Finish under the indicated time on the following tracks to unlock the corresponding car.

Car Track Time
Bulldog England 1:46
Conductor Kenya 2:06
Enforcer China 1:14
Grass Hopper New York 2:11
Howler Mexico 1:46
Monsta Hawaii 3:47
New York Taxi Germany 2:27
Rocket Japan 2:48
Rocket Russia 1.58
Skool Bus Egypt 1:07
Surgeon Australia 1:49
Tommy France 2:15

Driving tricks:

Dodge collisions:
To go right through a collision or on coming traffic simply do a turbo boost by pressing A, A. Then, perform a trick off the car.

360:
Push Left Or Right when your car is at the top of a ramp.

Flip:
Pop a wheelie on a jump (press Gas twice). Adjust your timing if this trick does not work at first.

Wheelie:
To pull a wheelie, press Gas twice while on a straight road. This will also result in a small boost.

Side wheelie:
Press Gas twice while taking a turn. This also helps to make sharp turns easier.

Barrel roll:
First, perform a sideways flip by pressing Gas twice while turning. Then move the joystick the opposite direction of the turn.

Flip Roll:
Start a normal flip during a jump, then press B, B, A, B, C-Up while in mid-air to earn 20 points.

Break Drift:
Press A + B while turning to slide. Also try this when hopping a ramp.