During the World Tournament Saga, when Gohan asks Goku to get a Senzu Bean, fly to Korin's Tower and get a bean from Yajirobe. Instead of giving it to Gohan, eat it. When you return, Goku will still give a Senzu bean to Gohan even though he does not have any. When you look in your invintory, you will see that you have 255 senzu beans.
first, Equip Goku/Goten or Vegeta/Trunks (remove all unneeded equips before) and do the Fusion Dance. As Gogeta/Gotenks, remove the equipment from the equipped character. The Fusion will keep the equips but you'll be able to re-use the equips on another character. This will keep working untill you run out of Fusion time
When these exhibits are found, take them to the Hercule Cafe in Hercule City to view them.
To access a store containing some of the best items in the game, visit the Kai's planet once you beat Buu and work your way to the right-most map and break through the crack in the wall. In here you'll find great items for levelling up, such as the Kiloton Gloves/Boots, and great armor with super high endurance.
While a conversasion press the L or R button and the talking screen will go up and down.
While preforming the Fusion Dance with Either Goku/Vegeta or Goten/Trunks, if you ignore the buttons it tells you to press, and instead press Up, B, Left, Down, A, you will successfully fuse every time.
Lure an enemy onto a Save Point with a strong character. Punch the enemy and kill it. Before you earn any experience from the downed enemy, the "Switch Character" menu will come up. Switch to a weak character. The character you switched to will gain the experience.
Everytime you get one of those, they are unlocked for the capsule corp museum, letting you see a specific item from the DBZ series.