One cool OS X tip that not everyone seems to be aware of is its zooming capabilities. You can actually zoom into your screen in the same way you can zoom into documents in Photoshop or any Word Processor. There are two different ways to do it.
If you’re using a Macbook or Macbook Pro you can can simply hold CTRL then use two finger scrolling on your trackpad. This also works if you have a scroll wheel on your mouse.
If you’re on a desktop, you’ll need to go into System Preferences>Keyboard and Mouse>Keyboard Shortcuts and make sure Zooming is checked. The default Zooming keys are:
Option/Command/= to zoom in
Option/Command/- to zoom out