You are limited to a total of five champions in a battle. Bring a champion of every elemental type, unless you know what specific element you will be facing. This will allow you to be prepared to attack any potential weakness that you opponent may have. Immediately before you starting a level, you will be given the chance to bring a random ally champion with you. This will allow you to accrue friendship points, which is needed to summon additional champions. When the level ends, you will have an option to befriend the person whose champion you summoned. If they accept, both of you will earn another friendship point bonus.
Combos
Try to set up large chains of combos. When you collect mana, any mana it touches will shift around in its location. Use this to your advantage by moving mana around. You can hold a mana piece for approximately five seconds, after which it will drop where it is currently located.
Elements
There are five elements to be considered: Fire, Water, Grass, Light, and Dark. Each element is stronger than another element, as follows. Fire is stronger than Grass. Grass is stronger than Water. Water is stronger than Fire. Light and Dark are stronger than each other. When you attack an enemy that is of a weaker type, your attack will do double damage. If you attack with an element that they are resistant to, your attack will do half damage. The names of various levels often provide a clue as to what you will be facing.
Fusion
Fuse spare champion cards into your existing champions to upgrade them. This will increase their level, and give them additional attack power and heal power. After reaching their maximum level, you can transcend them which evolves them into a new form.
Skills
Some champions have leader skills, which always remain active while that champion is slotted as your party's leader. Always choose the champion with a leader skill that is most beneficial. Champions also have a regular skill, which charges up during battle. Once fully charged, their icon will glow. You can then tap them when desired to have them use their skill.
Targeting
Your attacks will spread throughout all of the enemies evenly by default. However, you can change this behavior by tapping on an enemy. All of your attacks will be now be directed to that single target. Use this to eliminate a specific enemy as fast as possible.