Here is the low-down on all of the courses and their shortcuts! The Mushroom Cup is easy, Flower Cup is moderate, Star Cup is hard, Special Cup is expert, All Tour Cup is all of them put together in 16 action packed races. Mirror Mode is tough and has all of the courses in reverse.
Mushroom Cup
Luigi Circit
Shortcuts:0 Luigi Circuit is fairly standard. It has a Nascar setup with two turns, and two straightaways. The only advice is right before the turns there are two roads leading off the path giving you a double item block. Also, go up the walls and get a turbo boost on the turns.
Peach Beach
Shortcuts-1 Peach Beach is another basic course. You have to dodge the freaky-things on the beach because they'll try and flip you in the air. You can go to the left in the beggining of the race in the warp pipe for a double item block, but it consumes too much time. The shortcut happens when you come to the beach. Go to the left and make sure the tides not coming in. Go over the ramp and down the road(that is flooded when tide is in) and back to the main course.
Baby Park
Shorcuts-0 This is the easiest board in the game. It also is very fun but also very crazy. It is easy to lap someone and items are flying everywhere. It has 7 laps instead of the regular one.
Dry Dry Desert
Shorcuts-0 Dry Dry Desert is very fun. It is in a desert and it is very easy to go offcourse. There is a tornado but it is rather easy to steer clear of it. Also, the quicksand pit can be avoided by friving far off to the side.
Flower Cup
Mushroom Bridge
Shortcuts-2 Mushroom Bridge has a lot of cars, which can get very annoying when weaving in between all of them. There is one mini shorcut. Right after the first tunnel, go up the dirt road, preferably with a mushroom boost. This gets you a little time saved. The first shortcut is right off in the beggining. Very close to start, there is an opening in the rail. Go through it and into the warp pipe. Another shortcut is right before the bridge. Drive over to the side of the rail of the bridge and drive up it.
Mario Circuit
Shortcuts-0 Mario Circuit is rather easy. All you have to do is drive through the course. The hard parts come when you get to the dirt road. Watch out for the flowers on the long turn. Also, watch out for the Goomba a little later on and more flowers right before the finishing line.
Daisy Cruiser
Shortcuts-1 Daisy Cruiser is a giant cruise ship. It is pretty easy to navigate except for the turns and the giant room with all of the tables. Just get around them as quickly as you can. Shortly after that, there is a hole in the floor looking like a hatch door. Go down in it. Get the double item block and exit through the red pipe.
Waluigi Stadium
Shortcuts-1 This course is just like Wario Stadium in Mario Kart 64. You will need good drifting skills to get thorugh here. The hardest part is where you have to go through the fireballs and plants sprouting out of pipes. Do your best to avoid them. Also here is a gltich shortcut submitted by Yoshi Wannabe. Waluigi Stadium Glitch:
"Following the straight with the piranha plants coming out of the pipes and
the fireballs, there is a curve going towards the left. You may have noticed
that if you turn to thightly in that curve, the slope sends you in the air a
bit. That's where the shortcut is. What you have to do is line up your kart
in a way that you take that slope almost at its peak and jump towards the
jump near the end of the course. If everything was done right, the screen
should fade to black and Lakitu should place you near the jump at the end,
making you skip three curves. All you need for this is the correct angle to
get this to work, you don't necessarily need a mushroom or any other item
that speeds you up. The glitch saves about 2-3 seconds per lap.
Star Cup
Sherbert Land
Shortcut-0 Sherbert Land is kind of average. It is hard when it comes to the ice. You slip a lot of times. Be very careful at the home stretch where the freezy-freezes may freeze you(duh!) Be careful not to fall in the pool of water either.
Mushroom City
Shortcuts-0 This is the other course with traffic. When you go on this course, make sure to keep to the left of the course on all intersections. This will save you from the caterpillar bus and other trucks. At the end of the course stay in the middle of the road to avoid just about all of the cars and trucks.
Yoshi Circuit
Shortcuts-2 This course has many turns that require lots of skill to tame. The first shortcut occurs before the first tunnel. You will see an opening where you can see more of the course. Boost over it with a mushroom. The second shortcut is right after the first tunnel. There is a gap between the two guardrails. Boost throught it with a mushroom and into a secret tunnel.
D.K. Mountain
Shortcuts-1 D.K. Mountain is one of my favorite courses. It has so much high speed action. There is the D.K. barrel, sending you 195mph in mid-air. Then you go down a steep mountain side. The entire course is hard with lots of challenging turns. Make sure to go up on the side of the wall when the big pothole appears.Heres a shortcut:
DK Mountain Shortcut:
Once you get how to do this shortcut, it isn't hard at all. The shortcut is
jumping across that big hole almost at the end of the course, not the one
where you cross on the bridge at the end, the one where you have to go all
the way around to get past. The trick here as all about the angle at which
you take the jump, speed will get you in the hole if you don't jump
correctly, the brake is actually you're friend here. After going down the
steep mountain side, you'll come to many curves that turn in a "U" shape,
take the first one normally. The second one, though, should be taken while
drifting and braking around the curve. When you end that curve, immediately
start to drift towards the right, aiming to turn just after the guardrail.
The gap of the hole is rather short there, meaning it is easy to jump
across. Once you master this, the only thing that will be of bother is the
guardrail after the jump, let's just say that if you don't turn tightly
enough, you end up on the other side of the hole yes, but you'll probably
end up going to the left of that guardrail and back up the mountain.
Special Cup
Wario Coliseum
Shortcuts-0 This course is also loads of fun. It has so many turns, so be careful because there aren't many guardrails. It feels like a rollercoaster when going down it. The only peril is the turns, so just do some drifting and enjoy the ride!
Dino Dino Jungle
Shortcuts-1 This course is pretty hard to master. The first danger is the dinosaur. He is very slow, so don't bank on charging at the leg and hoping it will raise. The next peril is the three bridges. You should stick to the main path unless your awesome at steep turns. If you are, go to the right and on the narrow path. On the main path, you can go left to get a double item block. The shortcut is in the cave. Go to the right. Then, using a mushroom boost, jump over the gap. You must have a mushroom. Also, avoid the dinosaurs and geysers, which bubble before they blow.
Bowser's Castle
Shortcuts-1 Bowser's Castle is pretty hard at parts. The beggining is easy because you can easily avoid the whomp blocks. Also, you can easily avoid the fireballs on the metal floor. The short cut is the straightaway where the stone statue shoot the fireballs. There is a hole in the wall. Boost through the gap and into the other side. There are lots of hard turns in this course.
Rainbow Road
Shortcuts-0 This course is just like the Rainbow Road in Mario Kart 64. Except its shorter and more fun! Watch out in the middle of the course for the the hard turns with no guard rails. Just stay in the middle of the road and do drifting when nessesary. It is a lot of fun doing the speedy spiral going up.