Change your character to Luigi and go outside near the waterfall. If you are in the correct place, which is near the fence, turn your back to the little piece of land across the water. Do a backflip (R + B) and you will start twirling. Try to twirl to the little piece of land (not the steep side). Turn your back to the steep part of the hill and change the camera position so the it is showing your back. Jump and scuttle while holding Down and you will get up the hill a short distance. Then, just as you touch the ground press B(2) and hold it while pressing Down. Keep doing this until you get to flat surface at the top. Jump onto the red roof. It is steep, but it has a lot friction so that you will not slide down. There will be a rabbit, a "?" box, and three 1-Ups here.

Change your character to Mario, go outside, then keep going to the left. You will see that there is a corner formed by the castle. Do a triple jump, then wall jump kick on the wall. Then use another wall jump kick on the other wall and continue until you reach the top.

Change your character to Yoshi. Go near the waterfall, but not in it. Turn your back to the steep hill. Press B, then when you touch the ground press B (2) (Luigi's technique). Keep doing this until you are high up the hill. Try to slide down onto the little piece of land. Do the same thing up the hill and you will be there.

Go to the right side of the outside castle as Mario. Do a triple jump where the wall splits to two sides. If the last jump was close to the roof of the castle, do a wall kick twice and you will be at the top of the castle.

This is a useful trick that can help you get to the top of Mushroom Castle without having to get all 150 stars. You will need Luigi for this trick. When you have changed to Luigi, go to the castle grounds. Go near the fence near the waterfall. Look for a grassy platform on the other side of the waterfall (the side you cannot get to yet). As Luigi, turn your back to the fence and do a backflip (R + A), and aim for the grassy platform. If successful, you should land on it. Be careful not to land on the steep hill or you will fall into the water and must start again. When on the platform, face the castle wall, then turn your back to the steep grassy hill. Your view should be facing Luigi's front. Jump, then hold B, and press Up. You should be jumping backwards towards the hill. Remember to hold B to scuttle. This action is exclusive to Luigi, and it slows his fall. When you land on the hill, quickly press B, Up and hold it to ascend the hill. Do this quickly or you will slide back down. This is very difficult and requires practice, but it does work if you have the determination. Eventually you will land on a flat, grassy hill next to the castle top. Walk carefully to the roof. Note: There's a slope that surrounds the entire area; if you bump into it you will slide down. When you get there, you will see a red "?" block, three 1-Up Mushrooms, and, if you are Luigi, the last mini-game rabbit. When you catch it, you will obtain the key for the Super Mario Slot mini-game.

Use the following trick to get on the roof with 8 stars. Go to the far right side of the castle as Mario. You will see a slab of the castle where it meets the mountain. Triple jump then wall kick and you will land on the mountain. If you land on the edge it will not work. Once you land on the mountain, jump to the red colored part. If you miss, try to slide on your butt. Jump and you will be on the roof. Note: This only works with Mario.

With Mario, go to the right side of the castle. Go where the water was blocking the basement door. Run up to the right wall and do a triple jump. Do the wall kick back and forth on the two sides in-between the corner of the wall. He should make it up the ledge and grab it. This takes some time. With Luigi, go to the left side of the castle where you are next to the fence above the waterfall. Do the Backflip Jump and spin backwards towards the small grassy platform on the castle. Then do the Scuttle Kick with Luigi's back facing the slope. Gradually and slowly, Luigi will make it up the slope and on to the castle roof. This is not as difficult as Mario's, but it requires practice. You can also do this with Wario, but it is very difficult. First you have to master the Slide Kick. Go to the right side of the castle towards the slope away from the wall. Time your jump and when you make your second jump land in the corner of the slope in front of you and the one beside you. The third jump will land on the slope. In a fraction of a second, do the Slide Kick until you reach the top. Then, move towards the castle. You should be on the roof.