So first go in a place where some of the platforms are lit up but the others are hidden in the darkness, if you fall you drop onto a spike pit. Take out Baby Mario's Hammer and hammer in front of you. If it makes a clanging noise, there's a platform there and it's safe to walk on it. If not there's no platform there, so just try another direction.

In one of those places where you use the sunshine block, hit it, make sure the babies can't see it on their screen, and when there's a little light keep mashing start to open Stuffwell, close him, open him again, and close him again as fast as possible. Then that amount of light is left until you leave, or you get hit by spikes.

Hit the shine box and before it fades press start at the right time, it will be dark but light enough to see

The best badge you can get is called the Ulti-Free badge. It makes it so that if you use an attack item your stock doesn't diminish. This badge is only available from Fawfal (the underground badge guy) for 80 beeans. Only one of your party members in battle must be wearing it to effect the others.

One way is to buy a Coin Badge (A) if you don't have one. Equip it and go to Thwomp Volcano.
Go to the place where you find Gold Koopeleons. Battle them and defeat them with Bros. Items. At the end, you get 100-200 coins per Gold Koopeleon.

Another way is to get the Treasure Badge and defeat the Gold Koopeleons with Bros. Items. You should get some Golden Pants. Sell them to get a lot of coins.

Unlock the Blue Yoshi
When you see this Yoshi above his cage you will see two rows of colors. Go forward and hammer those colors, and the cage will open. Top row: blue-blue-yellow-yellow-red-blue-red-yellow
Bottom row: yellow-red-blue-red-yellow-yellow-blue-blue

The boss that looks like a mushrrom you have to beat his minions by atacking them with anything that has the best affect. Then when they are dead you have to hit the mushroom guy. Repeat without dying if possible.

Use baby mario and luigi to go ahead.Then,when you are about to enter a battle,quickely push A or B to switch to mario and luigi and to avoid the battle.

What is "Mario & Luigi 2" I thought that was partners in time?

Ok, just so you know (if you don't know already), once you get the Bros. Ball, it is very important you use it on the secret in the room before Thwomp Volcano's entrance. Then, when the pipe comes up, you can jump into it now if wanted. If not, wait until you get back to Toad Town from Star Hill and go into the time hole into the castle sewers. There is a chance you will see a person in a red coat. He will be inside the pipe. Use the babies to enter the pipe and then continue until you find an unusual place. Come back up through the ground and you will get a flashback of Mario & Luigi: Superstar Saga of Fawful. He is selling badges for beans, so buy the badge that has unlimited items in the description. Then equip the badge, and you will get unlimited Bros. Items. I'm not sure if it works on Mushrooms and stuff like that.