Pump up the Curves Dialog

Curves is a very powerful image adjustment tool. However in its default state it doesn't give you a lot of room to make your adjustments. However this can be easily fixed.

1. Click on that mysterious icon at the bottom right of the dialog box to increase the dialog box size.

2. Hold down the option (Mac) or alt (PC) key and click on the grid to display a finer grid.

Now your cooking with gas!