Super Mario Galaxy 2/Tips and tricks

Fast fireballs
You can dramatically increase Fire Mario's fireball output by repeatedly tapping while shaking the. cancels the animation, allowing you to immediately shoot another fireball, where normally you'd have to wait in between. This can come in handy against enemies of course, and also when you have to destroy snow statues or crates for hidden stars. This trick also makes the boss fight against Squizzard in ../Slipsand Galaxy/ extremely easy, as nothing he throws at you even has a chance to hit you if you just sit right in front of him and spam fireballs.

Infinite lives
You lose all your lives every time you quit and have to start back with almost none when you reload your game. Once you get to World 4, you'll never have to worry about lives again. In the first star of ../Supermassive Galaxy/, you can max out your lives to 99 very easily by jumping on the back of one of the Koopas on the second planet. When you land, start running to the right and when you get close enough long jump to the Koopa and land on its back. Make sure not to get the drill, or you'll have to purposely take damage to get rid of it. When you're on the Koopa's back, keep Mario or Luigi bouncing on it by holding when you need to, to keep your forward momentum. You get an extra life any time you can jump on eight enemies in a row, but unlike Goombas and other enemies you encounter in the game, these giant Koopas don't die, so starting at the eighth hit, you'll just continue racking up 1-Ups. You don't have to finish the level either, just pause and go back to the starship whenever you have enough lives.

Star bit farming
To unlock the final star in ../Grandmaster Galaxy/, you'll need to deposit 9,999 star bits with Banktoad. The easiest place to do this is on the second star of the ../Melty Monster Galaxy/. While rolling, try to collect the star bits out in space with the cursor at the same time as you run through the crystals as Rock Mario. At the end of the level, instead of jumping into the square ring where the star is, just roll off to the side to kill yourself and go back to the last checkpoint. Even if you don't collect every single star bit or get all the way to the end, it's still fairly easy to get around 100 star bits on each run. Additionally, there is an easy 1-Up mushroom right at the beginning and you also get 1-Ups every time you collect 100 star bits, so you're in no danger of running out of lives. When you've collected 999 star bits, remember to collect the star at the end of the level so you can keep your star bits.

Star bit tricks

 * Scattered around the game are circles of little stones in the ground. Spin inside them and they'll all turn to star bits.
 * Shoot a star bit at the gold circles you sometimes see in the ground, usually on boss planets, and a coin will pop up giving a health segment.
 * You can shoot star bits at normal enemies to stun them, but they also sometimes work to slow down bosses.
 * You can shoot star bits at the rocks Bouldergeist raises in ../Boss Blitz Galaxy/ to destroy them, leaving only the black Boo ones.

Yoshi's infinite flutter
Usually when you jump and hold with Yoshi, he'll do one flutter kick for more height. Using a glitch, you can continue flutter kicking indefinitely, allowing you to reach places you normally couldn't get to or that would take a much longer route. You can perform the infinite flutter by pressing and releasing while still holding, then releasing and pressing  again. You can continue doing this to gain great height or to move quickly horizontally for a short period of time.