To dream that you are in a competition, represents your need to grow and expand. Learn the value of endurance and perseverance. Also be more assertive.
If you dream of winning a competition, you have the necessary skills to accomplish a goal or solve a problem in your life.
If you dream of watching a competition, you may feel that others are passing you by in some way - socially or romantically - and you are just “sitting on the sidelines” of life. You need to get more confidence and be more involved in things.... My Dream Interpretation
To participate in a competition with strangers signals small expenses because of an unexpected trip; with coworkers, trouble getting a job promotion; and with family, heated discussions that could end violently. Earning money by betting on a competition is a positive sign: you will survive any problem; however, losing that money means you have to abide by the dictates of others.... The Big Dictionary of Dreams