The Dock is a wonderful feature of OS X. It's the home of your favorite apps, quick links to specific folders, and is very customizable. Simply drag and drop items onto it for quick access. To remove something, simply drag it off the Dock, and that item's link is gone. If you're like me, you use the Dock literally all day, every day.
As great as the Dock is, however, sometimes it can be in the way of getting work done. I sometimes find myself trying to edit parts of an image in PhotoShop, for example, only to get frustrated because I accidentally select the dock instead (obviously, this is when I am working on the bottom of the screen). You can go into System Preferences and choose to hide the Dock from view, but this is a semi-permanent change (to reverse the change, you would have to go back into System Preferences each time). I have a better option for you.
When you find yourself wanting to temporarily hide the Dock and get it out of your way, press the Command + Options + D (D for Dock) keys simultaneously. This will hide the Dock. When you're ready for it to come back to life, press the same key combination, and the Dock will instantaneously appear, just as quickly as it disappeared.