Super Mario Galaxy 2/Tall Trunk Galaxy

The Flotacious Blimp Fruit
You start out on a planet with a large tree on one side and a barren area on the other with a couple Spoings and a Yoshi egg. Go grab Yoshi and go back to the top of the planet with the tree. Up here you'll find a couple Blimp Fruit and a blue warp pad that will take you to a time trial with a bunch of Piranha Plants. The crystal below the Blimp Fruit next to the Whittle also has a 1-Up Mushroom. You need to have Yoshi eat a Blimp Fruit then fly up the tree, resting on ledges and eating more fruit while avoiding the Spanglers. Grab the Blimp Fruit next to the Whittle and float up to the left, where you'll find a ledge with another fruit. From that one, go straight up and you'll see another ledge with a fruit on your right. Eat the fruit and go up to the right to the Launch Star. If you go all the way to the top of the tree, you'll be rewarded with a Life Mushroom.
 * First planet


 * Second planet

This is a wooden cylinder with the surface cut away. This section is 2D and you can't fall off, so don't worry about dropping down below platforms. If you jump over the first Blimp Fruit, you can go down to pick up a 1-Up Mushroom. Continue going down, but stay far to the left and you'll find a green warp pipe above where you start that takes you to a room with three Chance Cubes. Eventually you'll want to use the Blimp Fruit to get up on the moving platforms overhead while avoiding the Paragoomba up there. Take the platforms to the right, where you'll get another Blimp Fruit and can fly up into a ? Coin. Follow the line of coins through another fruit and up to a grassy ledge. When you move to the right side of the ledge, you'll be able to see three of the star pieces you need to collect. Start off by dropping over the right side to collect the first one and use your flutter kick to land on the moving platforms below. Make your way over to the right to grab the Blimp Fruit and take it up into the next star piece, then over to the right to collect another fruit. When you get this second fruit, hold so you don't rise, and go to the left then release to get up to the next star piece. Drop back down to the platforms below while avoiding the spiky plants and grab the star piece under the platforms. You will fall down onto another grassy ledge with a Yoshi nest in the middle, and from here you can jump over to the left to grab the last star piece. Go back down to the platforms below and grab the Blimp Fruit over them, then head to the right again to pick up the second fruit. Use to get over in between the walls on the left again, but this time go to the top where you'll find the Launch Star.

This is another 2D planet inside a hollowed out log. Start off by jumping over the side and following the line of coins downward. You'll go around in a circle and eventually land at the bottom where a Goomba is waiting. Take the steps up to the left and grab the Blimp Fruit above. Fly up to the ledge up on the left with the Goomba on it and land there. You'll want to grab this fruit with Yoshi's tongue so you don't fly into the Spiky Plants. Head around them then back to the left through another fruit and up to the next ledge. Thread your way up through the Paragoombas and spiky plants, grabbing Blimp Fruit along the way and at the top you'll run right into the Power Star. When you finish this level, a pipe will appear on Starship Mario which will lead to a Luma Shop.
 * Third planet

Tall Trunk's Big Slide
This time the planet is full of Whittles and no Yoshi. The same crystal below the blue warp pad has a 1-Up Mushroom and the time trial is once again Piranha Plants. Since you don't have Yoshi and Blimp Fruit here, you'll need to take the swing up the tree. The first swing takes you to a ledge with another swing. That swing takes you directly to a third swing, which takes you to the Launch Star. The Launch Star flies you up to a huge slide in the sky. Just jump on the slide to start down it. Along the way you'll want to avoid spiky plants by going around or jumping over them and avoid the Wigglers and Spinys as well. There are gaps in the slide you will need to jump over also. In general it's a good idea to follow the coins, although it might take you a couple times to work out the best route. Along the way are two 1-Up Mushrooms and there is another one behind the tree when you finish the slide. Talk to the big Whittle by the tree and he'll give you your Power Star. When you finish this level, a Whittle will appear on Starship Mario.

Tall Trunk's Purple Coin Slide (Prankster Comet)
For this star, you will need to collect 100 purple coins for the Gearmo. There are 140 in total, so you don't have to get all of them. You start out at the top of the slide, so just grab the first four coins and jump in. This is just like the first time you did the slide with fewer enemies, but now you're forced to follow the route that picks up the most purple coins. When you have the choice between following a single row of coins or going for a double row, obviously you should choose the double row. Getting this star is more about staying in control while you're sliding, so keep practicing if you don't pick up the first time.

Green Stars
The first Green Star is at the top of the tree on the first planet above the Life Mushroom. Take the Blimp Fruits with Yoshi up to the top and flutter kick and jump off Yoshi to get the star. The second Green Star is up above the green warp pipe on the second planet. Jump over the Blimp Fruit and go down through the part where the 1-Up Mushroom is. Hug the left wall when you drop off that platform and flutter kick over to the star as soon as you drop down next to it. The third Green Star is in the gap after the 5th tunnel (the light colored one) with the spiky plants and the four angry Wigglers.