Aim for the sweet spot on the backboard. One of the reasons a lay up is such a sure bet is because you can always use the backboard to help ease the shot into the basket. When you're doing a right-handed lay up, the sweet spot is slightly to the right of the square in the center of the backboard. This spot absorbs the impact of the ball and drops it right down through the net.
You'll get two points no matter how you make your shot, but it's better to aim for the backboard instead of trying to just tip the ball over the rim. The backboard allows more room for error, but if you hit the rim funny the ball will bounce right out. There's nothing worse than missing a wide-open lay up when you have full access to the basket, so work on hitting that sweet spot every time.