Super Mario Galaxy 2/Starshine Beach Galaxy

Surf, Sand, and Silver Stars
On the starting platform, jump out into the water and swim to the Launch Star on the other side to fly to the planet below. This planet is a big beach and water open area. Here you'll find a lot of places to swim, some Crabbers, some Spinys and some Yoshi eggs. Your goal is to find five Silver Stars to create a Power Star. If you ground pound on the beach you'll get stuck, so spin to free yourself. On the other side of the hill with the hut on it by where you start, you'll find a blue warp pad to a time trial with some Crabbers. Using Yoshi, you can eat them up and spit them back out at the other Crabbers to quickly finish them off and get your three 1-Up Mushrooms. On the far side of the area, by the deep water, there is a green warp pipe that goes down to a room with a ? Coin. Like a previous ? Coin room, this one creates three patterns of coins that you can collect for a 1-Up and some star bits. There is a 1-Up Mushroom at the top of the hut on the hill and you can use Yoshi to grab the Blimp Fruit floating in the middle of the area to fly up the line of coins above it to a 1-Up Mushroom. There is also another one at the bottom of the deep water by the Urchins.

The Power Star will form when you have all five Silver Stars and will be on one of the little islands in the center.
 * Silver Stars
 * In a glass cage in the hut on the hill: Grab a Spiny from the beach with Yoshi and shoot it into the glass cage to break it.
 * Above the statue: Use the pull flowers to get to the top with Yoshi, then flutter kick to the Silver Star.
 * At the top of the tower: Grab a Spiny off the beach, then go over and break the glass cage by side of the tower with the Blimp Fruit in it. Use the Blimp Fruit to get up to the top of the tower.
 * Floating over the deep water: Grab a Dash Pepper with Yoshi and run across the water to pick it up.
 * Above the rolling platform in the deep water: Stand on the side of the platform near the water to roll it up so the pink jump pad at the top is facing upward. Jump up to the top and bounce up to the Silver Star

Climbing the Cloudy Tower
Once again, jump out into the water and take the Launch Star down to the beach. It's a little different from the last time you were here. Instead of Yoshi eggs and Spinys, you'll be on your own and the Piantas will throw you around. You can get the Pianta by the hut on the hill to throw you over to a 1-Up Mushroom, and there's one on the top of the hut as well. There is another 1-Up Mushroom above the rolling platform in the deep water, one underwater where the Comet Medal was and both the warp pad to the time trial and the green pipe are the same as in the last star.

You'll see that the tower is now surrounded by clouds, so you'll want to use Cloud Mario to get to the top. There's no Cloud Flower on the beach, but if you swim down into the deep water and up into the structure at the end, you can get up to the top where you'll find a red button. Ground pound the button and a Cloud Flower will appear on one of the little islands. It also activates some of the water cannons, which will shoot you up to the coins around the tower. Go grab the Cloud Flower, then jump into one of the leaf boats nearby. You can navigate in these by running in the direction you want to go. Take the boat over to the tower so you can start climbing up the clouds there. Jump onto one of the low clouds and use it to get to one of the clouds a little bit higher. From here you can use your own clouds to get to the top of the tower. Grab the Cloud Flower up there and use it to get the Power Star above the palm tree.

When you finish this level, a Cloud Flower will appear on Starship Mario.

Purple Coin Beach Dash (Prankster Comet)
You'll be on the beach for this star with Yoshi and you will need to grab a Dash Pepper and collect 100 out of a possible 140 purple coins in 35 seconds. There's really not much to this star, just grab Yoshi in the beginning, eat the Dash Pepper and start following the purple coins. It's a little difficult to control Yoshi while he's dashing, but as long as you stay in the center of the double and triple rows of coins for the most part, you should collect the 100 coins easily. As soon as you do, the Power Star will appear and the countdown disappears.

Green Stars
The first Green Star is above a palm tree near the Blimp Fruit floating in the middle of the water. Walk over to the Blimp Fruit with Yoshi on the side of the hole it's over closest to the Green Star and grab the fruit with Yoshi's tongue as soon as you get in range. Head straight back to the Power Star from there and you should just make it before the Blimp Fruit wears off. The second Green Star is floating in the air above the deep water near one of the Silver Stars. If you have really good aim you can ride Yoshi out there with a Dash Pepper and jump into it, or just swim out there with Yoshi and flutter up underneath it and jump off him in the air.
 * Green Star 1 or 2

This Green Star is high above the rolling platform in the deep water. Swim down into the structure and up to the top so you can pound the button and release the Cloud Flower, then use a boat to go over to the rolling platform and jump up to the Green Stars using backflips and your clouds. You can make it up to the Green Star starting right on the boat, but if you can't quite make it you can roll the platform over and use the jump pad on top for some extra height.
 * Green Star 3