I love learning quick shortcuts for various applications, especially when it means I don't have to use my mouse to adjust settings, etc. To quickly adjust the volume in iTunes, just place your mouse arrow over the top of the horizontal volume bar. Rather than clicking the bar to adjust the volume, just scroll up and down. Also, if you need to quickly pause a song, make sure your iTunes window is open and click your space bar. This will instantly stop your music. I suggest giving them both a try!