Stamp: Crying Sprixie
Enter the tent from the map to find a stamp inside.
World 3-1: Snowball Park
Shortly into the level, you'll encounter this group of flying enemies. Take them out to access the small nook they were covering - there's a star inside.
Right after the large icy area with the three Skating Goombas, you'll spot a rabbit. Catch him to earn another star.
You can't miss this one just before the warp pipe, but it can still be tricky to grab. Be careful walking the narrow icy path to your prize.
You'll need to wear the Propeller Block through the whole course to get this. Just before heading through the warp pipe, propel yourself into the air to spot the level's last star in a tiny alcove.
World 3-2: Chain-Link Charge
You'll spot this overhead while moving through the course. Use a Cat Suit to scramble up the moving chain-link, or alternatively, use a wall jump to reach the star.
Just before using the warp box, jump to the clouds to your right for another star. It's a tough jump, so a Cat Suit or Tanooki Suit may help.
Stamp: Cat Suit Luigi
Just past the checkpoint, there will be a blue wall on your left. Use a Cat Suit to scramble up it and reach the stamp above.
Immediately above that same blue wall is a cat paw gear. Swipe it a few times with the Cat Suit to temporarily raise a wooden platform to your right. Quickly hop over there and scramble up the platform to reach the level's last star.
World 3-3: Shifty Boo Mansion
When you reach the dual staircases, take the upper one. Hop into the Boo painting to reach a secret, rotating room. Grab the star inside before time runs out.
Continue to your right on the upper floor. Jump onto the couch up here, and it will raise you to the stamp.
Inside the library, make your way up the shifting bookcases to the upper left. From here, start dropping onto the platforms as they retract. A star will be revealed when you reach the bottom left bookcase.
Before heading through the last purple door, jump onto the couch to the right. This will take you to an upper ledge with a warp pipe. Jump in, and it will burst into a group of Boos…and a star!
World 3-4: Pretty Plaza Panic
Turn around at start of the level to spot this.
When you reach the pond with coins moving through it, you'll spot a rabbit. Catch him to earn a star.
Stamp: Little Peach
Immediately after, you'll cross some rotating platforms with Piranha Plants. Hop across the platforms on the left to find a Peach Switch. Use Peach to hit it and reveal a stamp.
Just before the level's end is a cloud. Bounce off of a Goomba to reach it and be launched to a secret area. Dash through to find a star at the end of the course.
World 3-A: Magikoopa Blockade
Simply take out the Magikoopas to earn this star.