Right after the first triple jump spot there is another jump leading onto a hole in the mountain. Some say you have to stay to the left of the jumps to do it right, but you can come from the left, right or go over the three jumps. You can make it through using a mushroom or a star without jumping, but without them you have to jump if you are a heavyweight or a middleweight. Lightweight can sometimes make it without jumping, but I recommend you do just to be sure. This saves a good 15 seconds at least.
If you don't like that shortcut there's another one that isn't as good but does help a bit. Before the triple jump spot from above you pass under a rock arch, instead of going through, go around it on the right. If you catch the tides right, a small path will be there, if not the water will slow you down a bit but it will still be worth it. But watch out for the crabs along the way!
Mario Raceway
To take this shortcut, you will need a Mushroom. The point where you will need to jump to get over the wall is just before the fourth turn (the hairpin turn around the giant mushroom). After the third turn, veer slightly to the left, and go slightly up the hill on the left. Turn sharply back towards the wall and hit your Mushroom boost just before you leave the road, jumping at the same time. You'll want to aim just to the right of where the sections of wall intersect. If you make the jump, you will come down near the giant green pipe. If you manage to take this shortcut every lap in Time Trial mode, and do the rest of the course perfectly, you will be able to complete the track in under one minute. This trick is extremely difficult to perform. I did manage to jump over the wall by the giant mushroom, but it didn't put me anywhere close to the green pipe, so either I did it wrong, or that is a mistake. What I accomplished did save some time too.
Toad's Turnpike
At the beginning by the first crossover, start a mini turbo slide before you reach the place where the roads cross, then jump the rail to the right. Lakitu will pick you up. Hold A + B one second before he puts you down. When you hit the ground, immediately go right and jump the rail again. This time you will go through the ground. You may land on the road or you may land in the water. Or sometimes you don't make it. If you land in the water you will be put on the road where the short cut comes out.
This trick is extremely difficult but you'll skip about half the track if done correctly. I have tried this but it never worked. I'm sure it does work since I have seen it in so many places and judging from some of the times people have submitted to me.
Frappe Snowland
When you start, do a U-turn and drive backwards. Keep driving until you get to the end of the bridge. At the end, jump off the right side of the bridge and onto the snow. Keep driving, and Likitu will pick you up and place you back on the bridge. (If you are placed back on the snow, then it didn't work.) If you executed this correctly, you will have advanced the entire lap. Repeat this trick (after crossing the finish line) and you should be able to finish the track in 45 seconds or less!
Choco Mountain
Right before the big loop there is a road to the left and up a bit(it's where you may have fallen off before). Do a powerslide and you can jump the wall. If done correctly you can save about 10 seconds. You cannot be in 50cc because there will be a fence there (but who plays on 50cc anyways???).
Wario Stadium
Right at the start there are four mounds of dirt. Do a slide turn to turn 90 degrees along one of the mounds. As you hit the wall hit the jump button and you should fly over the wall into the wide open part with a lot of mounds. This completes about one third of the course in under five seconds! In the same area that you land drive towards the far left corner. This one is really hard, but if you jump off the mound just in front of the corner you should hit the wall and hop up onto the dirt. Lakitu will put you down just before the finish line. Combining these two shortcuts can give you 10 second laps. I find the first part is very easy to do with the heavyweights, sometimes the lightweights will bounce off the wall instead of over. The second part, on the other hand, I have done only twice after many tries, and not right after doing the first part.
Royal Raceway
After the first hairpin turn (you know the one), go off the road to the left about halfway between the hairpin and the next turn. Aim for the dark spot on the opposite shore and use a Mushroom to boost you over the water as you jump. If you make it to the other side, Lakitu will pick you up and put you back on the course just before the monster jump over the lake! You can save about 15 seconds per lap with this shortcut. To save even more time, use a Super Mushroom just before you hit the second pair of arrows on the super jump across the pond. Once you jump, turn as far left as you can (try to land on the flat part of the mountain.) If you make it, Lukitu will pick you up and put you right in front of the finish line! I have never tried the first part. I did the second part without using a mushroom, but I didn't find it saved all that much time. I'd rather take the regular way and get two items.
DK's Jungle Parkway
Turn around and jump into the wall to the left of the exit from the tunnel (making it the right side from with respect to the way you are facing). Your angle of approach is important. If you angle too far to the left, you will fall back into the tunnel. If you angle too far to the right, the trick won't work. You want to fall into the "dark space" behind the wall. Lakitu will pick you up. If he puts you back on the track, inside the tunnel, the trick worked. When you go across the finish line from there, the lap counter will advance one lap. If Lakitu puts you back on the track outside of the tunnel, the trick didn't work. If you pull it off, you can get a 20-30 second lap on this course.
Rainbow Road
As soon as you start there is a huge slope. Before the slope gets steep, jump and turn to the left (or turn then jump, it doesn't matter). With practice you will be able to land on another part of the track, saving a least 30 seconds. Some say you need a speed boost or mushroom, but it usually makes me jump too far. I watch the ground and jump at the second bright yellow stripe on the ground.
