Super Mario Galaxy 2/Yoshi Star Galaxy

Star 1: Saddle Up with Yoshi
Run down the path in front of you until you reach the area where you see a Yoshi egg that is trapped in a forcefield. Defeat the Magikoopa to deactivate the force field and jump onto Yoshi, who comes out of the egg.

Proceed towards the muddy path and eat the fruits that are in your way. Further down the path is a large shining fruit. Pull it out of the ground to make a Launch Star appear. Use it to fly to the second area, which is a small planet with many crystals on it. Break the crystals until you find the Launch Star.

In the third area, jump on the jump pad to get to the ledge. Find your way up the small mountain; use your pull technique to drag the spiky plants off the ground. At the top of the mountain, use your tongue to grab the flower and jump towards a small planet. Use the Launch Star to fly to the fourth area.

Grab the checkpoint flag and head down the path. Use your pull technique to pull out platforms with green circles on them. On the second ledge, jump onto the moving platform and use your tongue to swing on the flower. The tricky part is to swing right when the moving platform is at its lowest point. Continue up using the vertical moving platforms to get to the very top of the area. Swing on the flowers to reach the shiny Power Star. Headbutt the large crystal twice to release the Power Star and swing on the flowers again to reach it.

Items
Right after freeing Yoshi in the first area, find a long round hill sticking out of the ground. Jump on the jump pad to get up on top of the hill to obtain the Comet Medal. In the second area, there is a chance cube. On the second ledge of the fourth area use your pull technique to pull out the wooden platform and get the 1-Up mushroom.

Star 2: Spiny Control
Run down the path and free Yoshi from the egg. Proceed forward until you find a large group of glass cages and spinys. Eat the spinys and spit them out at the glass cages to break them. Once you break the cage the contains the launch star, fly off to the second area.

The second area contains three cages that are floating in midair. Destroy the one in the middle to free the Luma. The Luma will turn into a Launch Star, leading you to the third area.

Use your pull technique to pull out the platforms with red dots on them. The next part is tricky. Eat a spiny, pull out the wooden platform and fire it at the glass cage to free the Launch Star. You must do this before the timer for the platform runs out.

The fourth area is the boss area. The boss will throw spinys at you. Eat the spinys and spit them back out at the boss to damage it. Be careful of the boss's lightning. Once you hit the boss three times, he will release a Power Star.

Items
During the blast off to the third area you will see another Launch Star in the air. Spin at the right moment to fly to an extra area. There is a 1-Up mushroom and a red Life Mushroom in this area. The 1-Up mushroom may look hard to get because it's upside down but it is really not. When you are on the small circular platform you will not fall off the edge. You will just go upside down and reach the mushroom. In the third area a not so hard to spot 1-Up mushroom is located above one of the wooden platforms you can pull out by using your pull technique.

Star 3 (Prankster Comet): Spiny Rainbow Romp
The Prankster Comet in this galaxy requires you to use the rainbow star power up to defeat all of the spinys in the area before the time runs out. This comet mission is very hard and very stressful so you may have to practice multiple times to finally be able to defeat all of the spinys. The trick is to stay in rainbow star form and avoid mud. Even only one second in mud could ruin your chances of completing the mission. Long jumping is also useful for this mission.