You can get energy the following way:
- Level up your XP (Energy is fully restored with a new XP level)
- Wait until your energy points restore
- You sometimes get energy points for beating match-3 levels
- You sometimes get energy points for completing collections and quests
- You can buy energy with your crystals in the Shop
- Receive energy as a gift from your Facebook friends
- You can also buy energy in the Energy shop. To do it, simply tap the energy bar in the city.