Rule no. 1 - do not celebrate too early.
After a Burrillville High School player tossed the ball high in the air and backwards with the intention to run down the clock, his team thought they had the title in the bag, and rushed the court to celebrate.
Only, they were too busy celebrating to realize that a Chariho High School player caught the ball, and called a time out before time expired. Chariho went on to win on a last-second basket, and we can all feel Burrillville's second-hand embarrassment.