HOW TO Improve scrolling with your Magic Mouse
1 Change tracking speed
Now that third-party utilities are no longer available, changing the tracking speed in the System Prefs > Mouse pane is the most obvious way to gain better control over scrolling with the surface of an Apple Magic Mouse, but many find that still insufficient for precision.
2 Find more options
Instead, use the full controls in the Accessibility pane. Select the Pointer Control item at the left, then click on the Mouse Options button on the right. This not only provides better control over scrolling speed, but if you turn off inertia, scrolling should stop overshooting.
3 Use with Magic Trackpad
Another solution you could find even better is to supplement your mouse with a Magic Trackpad. You can use both devices at once, and the trackpad’s gestures are applied over a larger surface, improving precision for actions such as scrolling when you need them.