"to kick it up a notch" is an idiom which means to increase the level of something. You use it when you're speaking or writing informally. For example, you and a friend are listening to the stereo. You want him to turn up the volume a little. You say, "Hey, I can't hear the music. Kick it up a notch." You're working slowly, but then realize you won't finish your work on time. So you decide to kick it up a notch. That means you decide to work faster. Your example about the party is another correct use of "kick it up a notch."