Choose File > New Smart Playlist.
To have iTunes add songs that match specific criteria, make sure "Match the following condition" is checked, then make your selections from the pop-up menus.
For example, you might want iTunes to only add songs that are by a particular artist, or songs with at least a four-star rating.
To add additional matching criteria, click the
Add (+) button.
To make the playlist a specific duration or size, select "Limit to" and make your selections from the pop-up menus.
To include only songs that have a checkmark beside them in your library (and that match your conditions), select "Match only checked songs."
To have iTunes continually modify your Smart Playlist as songs are added to or removed from your library, make sure "Live updating" is selected.
To create your Smart Playlist, click OK, then name the playlist in the Source list.