Spotlight is great at searching your Mac. I like to use it to launch Applications that I don't keep on my Dock. For example, I use Skype, but not too often, so I don't like to clutter up my dock with it. If I need it, well, it's just a few keystrokes away.
Click on the 'Spotlight icon' on the menubar or hold down 'Command + Space Bar'. Either one of these will bring up the Spotlight search menu. Start typing in your application you want to launch, and before you are done typing.. it will probably find it.
To launch the app, simply click on it, or if it is the top hit, you can even launch it by holding down 'Command' and press 'Return/Enter (depending on your keyboard)'.