You can unlock a whole range of side stories by earning a specific amount of love, friendship, or fans. You don't need passes to play these side stories but they don't earn you any gems, love, fans, or friendship.

If you're to focus on any of the three especially, it should be fans.

In the main menu screen, scroll to the option "replay all of the stories" and you will be able to start the main story over from the beginning, this time you could make different choices.

If you need to sing a Demi Lovato song or tap along to the beat it's a good shout to listen the song on Youtube prior and to check out the lyrics too. The better you are at this, the more fans you'll earn.

When you're out of passes use the time lapse cheat and go to your device's settings menu and change the time forward by more than 4 hours and you'll get free passes.