On the base floor, enter the door at the top left. Jump through the window at the right. Now you are in 'Princes Secret Slide'. At the bottom in a block there is a star.
Slide into 'Princes Secret Slide' in less than 21 seconds down and there will appear another star.
In level 3 ( the first swimming world ), jump through the most right black hole in the wall and another star will appear.
In Wingcap Switchcourse, collect all the red coins. On the tower you will see a star.
Catch the golden bunny in the basement. It will give you a star if you let him walk.
In Vanishcap Switchcourse, collect all the red coins. The star will appear at the end of the level.
In the first bowserlevel, collect all the coins. The star will appear at the end of the level.
Talk to Toad, who will be standing at level 6, the Hazy Maze Cave. He will give you a star.
Repeat 5
In Metalcap Switchcourse, collect all the red coins. The star will appear behind the button in the water.
In the second bowserlevel, collect all red coins. The powerstar wil appear at the end of the level.
At the floor one below the top floor in the center of the great hall, talk to Toad. He will give you a star.
Collect all the red coins in the last bowserlevel. Again the star will appear at the end of the level.
On the top floor, go left. Jump into the hole in the wall. Let yourself drop into the hatch. Collect all the red coins. The star will appear on top of the big cloud in the center.
Talk with Toad. He is on the top floor. He will give you your last star.