PRINCESS SECRET SLIDE: In the 2-star room, jump in the right picture of Princess Toadstool.
WING MARIO OVER THE RAINBOW: Soumerault/triple jump near the clock. You'll find a hole - go in it.
SECRET AQUARIUM: Jump in the black hole above the toad in the Jolly Roger Bay room.
CAVERN OF METAL CAP: Go on Dorrie in Hazy Maze Cave until you see a door. Take it. You'll find a pool of slime. Walk into it.
TOWER OF WING CAP: After you get 10 Power Stars, light will appear. Press C-up and you'll enter it.
VANISH CAP UNDER THE MOAT: Stomp two certain pillars in the basement. All water will drain. In the moat, there's a hole. Go in it.
Every other secret is really easy to find. Bye!
Added by: MarioManiac164 Jun 27th 2012, ID#6612