Smart Playlists are an iTune’s feature which allows you to create your own playlists from the songs you have downloaded to your iTune’s account library. The options for creating the playlists are being able to create a playlist based on dates that you downloaded the music, ratings or other criteria. This means that you will have to rate your music if you want to create a playlist of particular ratings, so the first thing to do is rate the songs that you want to make sure are included in this particular playlist.
When you make a choice of what playlist you would like to make to help optimize your iPhone storage a popup window will display and you can choose from ratings and then greater than or less than. For example if you want songs rated greater or less than five stars, you will be able to make that choice. From that point, you can just click on the plus icon.
After you have clicked the plus icon to create a new playlist, you will see that a second row has been created in the playlist window. You can then choose the size from the drop down window and choose “is” from the second window. That will allow you to choose the amount of disc space you want to use on your iPhone for the music that you’ve chosen. When your playlist syncs to your iPhone, it will sync the amount that you specified so you aren’t using too much of your iPhone space for music.