Yeah, we know believing in yourself is sometimes easier said than done.
You want to be a great athlete, but it's hard not to compare yourself to your teammates, and even the pros. Our advice, stop the comparisons and trust in your own game.
The law of attraction is funny like that -- the more you believe something the more likely it is to become true. It's like in "Star Wars" when Yoda warned about the temptations of joining the dark side. Negative thoughts hurt your ability see things clearly, and prevent you from improving your game.
The trick is to start by giving yourself some credit. Before a game visual yourself playing. Basically, sit and day dream about how the game will play out. See yourself passing the ball, running down the court and scoring point after point. If you're scared of making mistakes during the game, then figure out how you will work through those problems. This will help you get rid of the game day nerves and make it easier for you to believe that you can play well.
The next step, is to practice.
The more time you give yourself to practice, the more likely you will be to be confident in your abilities. Think of it like studying for an exam. You wouldn't just take a test without cracking open a book first, so why would a game be any different?
With some work, you can gain the confidence you need to hit the court with a winning mindset, and play your best.