From the start you’ll notice there are plenty of Goomba Towers around. Slide down the ramp and clear the Gooma Tower for a 1-Up Mushroom . Atop the steps is a ? Block with a Mega Mushroom . Use this to rush right, then leap up into the Stamp before falling all the way down. Defeat all the enemies down here and move through the Blurkers to Green Star #1 if you still have the Mega Mushroom . If you don’t, just blow on the GamePad Microphone.
Head back left to claim a Super Leaf from the a block then doubleback right to the Checkpoint Flag . Head into the next area that just happens to be water-filled. Mind the Bloopers and airvents so you don’t take damage. After the second Spike Block swim up into an alcove with a ? Block that yields another Mega Mushroom! Use this to plow through to the Mushrooms Trampolines, ground pound on them to blast holes in the bricks above so you can find Green Star #2 .
Swim right but don’t enter the pipe, swim up into the light that’s coming in to reach a bonus area. Hit the P Switch then grab the Mega Mushroom from the ? Block so you can collect all the Blue Coins much faster. When you collect all the coins you’ll spawn Green Star #3 and can make your way to the Goal Pole.