Cheats

Yoshi disappears- Yoshi is very picky about when you ride him, if you are riding him and he falls into the water, then he go into his egg; also if he is low on food he will go into his egg also.

Yoshi juice- After you get Yoshi, spray juice, then tap A softly because if you don't a large amount of juice will appear and in some places, that may be trouble.

Yoshi's taste- After Yoshi swallows a fruit, it will turn orange, purple, or pink. These colors will tell you what kind of fruit it is. ( example: if Yoshi eats something and it turns orange, that means it's sour, or if he eats something pink it's sweet, and lastly, if he eats something purple, that means it's spicy.

Hints

Free coins- In Delfino Plaza, spray all of the wanted posters of Mario. You will then get a coin.
(Not all of the posters give coins, only some.)
In Delfindo Bay, spray and aim into an open window, and you will get coins.
You can eat birds as Yoshi in Delfindo plaza, or look in the manholes also in the plaza and you will find coins.

A hidden tunnel- By Fruit Street, walk on the beach, then while you are getting a top view of Mario, you will see a tunnel going underground that is covered in sand. " Ground Pound" on the sand and you will get your reward.

Coins on Gelato Beach- At one of the four points that you must spray, Yoshi is there. There is one in the middle of the Island and if you go there, you will get a blue coin; also if you go into the water, you will find a few more coins.