At the jersey selection screen before a game, press Y, then enter one of the following codes to activate the corresponding cheat function:
Make a perfect team, then simulate the whole season. At the end of the playoffs you will get a call that says how many points for season tasks you got. If your team did well you will usually get around 8,000 points. This takes time, but it also gets you a lot of points.
Take a created player and edit your gameplay settings to all shots 100. Set the quarter length to 2 minutes and shoot 100% for the game. You should get about 2,500 points every time you do this.
To get easy points, get an outside scorer and press LT + X. He will put the ball behind his back and lay it up. It cannot be stopped even by an inside stopper and will always work.