The first Star Coin is floating above the Hammer Bro at Point 1. Use a fireball or shell to defeat this enemy, then hop onto the Blocks and collect the Star Coin.
Pass through the Red Ring at Point 2, then collect the red coins that appear to the right.
The last few red coins are near a Boomerang Bro. If possible, use a fireball to clear out this pesky enemy before you hop onto the Blocks to collect the last of the coins.
The second Star Coin is located in a hidden area. Enter the pipe at Point 3 to find it.
The Boomerang Bros. can make it difficult to collect the Star Coin. If you still have a Fire Flower power-up, use your fireballs to clear out both of the enemies before you drop down from the upper platforms.
The Big Bro at Point 4 is standing on a sturdy platform, so you can’t attack from below. Avoid this enemy’s hammers and powerful ground pound attacks, then jump up and clear it out with a fireball or stomp on its head.
After you deal with the Big Bro, move left to find the Star Coin floating at Point 5.