Fight in level in Z Battle Gate at Kami's Lookout. For example, play as Krillin vs. Yamcha. During the fight, go over to the main building and put it between you and the enemy. When you fire your finishing move, you will destroy the building. Go over and look at the rubble. There will be a column stump remaining in the middle, and a Dragonball on top of it. It does roll off -- if it is not on top, then it is somewhere on the ground. Quickly grab it and make sure you defeat your opponent, or you will have to get the Dragonball all over again. All seven Dragonballs will appear one at a time at this location randomly. Just fight in the level seven times to get a wish from Shenron. This is very useful, as every time you get a Dragonball and complete the level, you will also get another Z Item Fusion, which are valuable, and a random Z item. Do this as many times as desired.

In Story mode, select the Buu Saga and look for the level that takes place on top of Kami's lookout (SSJ3 Goten vs. Super Buu). During the fight, destroy the main building on top of Kami's tower. There will be a Dragonball in the rubble every time. Repeat this as many times as desired. Note: You must successfully complete the challenge each time in order to receive the Dragonball at the end of the match (for example, finishing off Super Buu with the Volleyball attack).

Go to the fight with Chiaotzu vs. Guldo. Burst through the few islands in the stage and locate the Dragonball by using your radar. Then, defeat Guldo. He is not much of a challenge. Repeat this to get all the Dragonballs.

Go to the Saiyan Saga and get to the part were you must defeat Krillan with Yamcha or vice versa. Go to the building in the middle of the look out (the biggest one). Destroy it and get the Dragonball there. Defeat the enemy and you will get the Dragonball at the end. Do this seven times (always a different Dragonball) to get all of them.

Go to Sayain Saga and Krillin vs. Yamcha. Blow up the big building and get the Dragon Ball, then win. Repeat this a total of seven times.

When fighting Super Buu in Buu Saga with SSJ3 Gotenks, the Dragon Ball is inside of the lookout house. Get the Dragon Ball and defeat Buu with the super move. Repeat this until you have all seven Dragon Balls. Keep doing this and you will unlock everything that requires a wish to obtain.