Turn Off the Magnet Feature
If you turn the magnet feature off only one character at a time moves around the map instead of your full party. This will allow you to start in an advantageous position for quick attacks straight away as battles start based on how the characters are arranged on the level map.
Individual Skills
Pay attention to individual skills the characters have and look to take advantage of them whenever possible. Khem for instance adds Mega Heal to an attack, a skill which heals an allied character who is involved in the attack.
Chain Attacks
Always look to put together chain attacks whenever possible as they they raise your stats and help level your equipment.
Attacking Elements
Remember that when you attack the same element it will result in half damage, while attacking the opposite element gives double damage.
Maneuver Enemies
A good tactic is to maneuver enemies into bombs or other obstacles which you have placed beforehand using skills.
Power Ups
Keep an eye out for power ups for your party. Like placing your second character for instance in a pincer next to the glowing blue 'P' icon to increase attack power.
Extra Energy
If you go to the Achievements screen you will get extra Energy for the sign-in bonus. Once you have 60 energy stored up you will have enough for two new draws.
Synced Play
If when given the choice you choose to play a story level in Synced mode you will earn greater rewards. When you select Synced Play your Guardian's level and overall power will be capped at a point specific to the level you choose to ensure that completing it is still a challenge.