Like the battery, Apple laptop displays by default are not optimized right out of the box. In some cases the complete opposite is true. You may power on your computer and find that the display looks very poorly and colors are hued and tinted. This is when you are going to want to calibrate the display. This is also a very simple process.
First, you are going to want to navigate to your System Preferences menu. It can be found in the dock (the icon with gears), or can be accesed through the commands: Finder > Applications > System Preferences. From this menu, click the display icon located in the second row "hardware". This will bring you to a window that has two tabs (display and color). Click the color tab. After you have done this you will see your display in the left selection menu. It will be labeled something like "MacBook display". Click to select it, then choose calibrate. This will open the Apple display calibrating assistant and colorsync utility. Put a checkmark in the option box for "Expert Mode" and click continue. In the next couple of steps the assistant will show you a box with an apple logo located in it. For the two sliders, it will give you instructions on how to calibrate. For the most part, all you have to do is blend the Apple logo with the background as much as possible.
After you have completed the first steps, it will ask you to set the native gama. It is best to leave this slider alone at default Mac gamma. The last step is to set the white point. Again, it is best to use the pre-configured white point. You should now have synced both your battery and your display and any changes should be noticeable immediately.