You first must find a tournament site near you, which you can do at yugioh-card.com. Then you must go there and sign up.
YU Gi Oh tournaments are a fun way to interact with people with common interests. They are also ways to win some awesome prizes. Go and duel dudes!
Yugioh-card.com
No, but nearby cities may work. check http://www.yugioh-card.com/en/events/tournament_locations.html for other cities that have OFFICIAL tournaments.
Usually depends on the tournament and where it took place. The winner usually gets a booster box and sometimes you can get money, additional cards and promotional cards too as well as a official...