Listed below are 30 places you can search for the Dragon Balls. There are only 7 dragon balls so you may not find them. It takes 3 days to search in each location. If you encounter someone else in the same location where you are searching you will have to battle them to the death. Unless they are on your team.
If you get killed you also lose all your dragonballs and they go to the person who killed you. Good luck!