By avoiding bullets and stomping enimies
Level 2
Complete the first star from the Grandmaster Galaxy and have 9999 Star Bits stored in the bank.
Rosalina will tell you.
It's a hidden star and can be found by simply going to any level
7 times you must lose a life in the galaxy and then the super guide engages.
To get her as a file icon, you need to get 120 stars and clear the level in Bowser's Galaxy Generator. To get her on Starship Mario, you need to get all 240 stars.
You must really stink, because that level is easy!
When you complete the bowser level after you get 50 stars and you have to complete the bowser level twice to get him
Try for the 122nd star, or just play on any level you want.
There are a few levels with toxic water. You'll need to be more specific.
yes and no. there's a secret level in the space junk galaxy with a planet that looks like Yoshi in it, but the actual character doesn't make an appearance.
You meet him a lot on different galaxies, but when you beat the last level (i think) you can play as Luigi any time!