When fighting monster, speed up the fight by holding L or R. If you hold L the fight will become quicker, whereas if you hold R the fight will become slightly faster than holding L. If you hold L + R ,the fight will be even faster.
Blue treasure chests can only be opened once all the enemies on the screen are cleared. Afterward, once you open the chest, you will recover 30% of your HP and MP. To know how many enemies are on the screen, look at the check on the bottom screen, indicating that the enemy is defeated. Blue chests often contain armor and weapons.
To gain experience after battle, use your stylus to tap the icon of your character. Their eyes should now be closed. After defeating enemies, you should see them turn into golden balls, which are your experience points. However, you will not receive any items. If you wish to gain items, tap on your character's face again on the bottom screen with the stylus. His eyes should now be open (Combat mode) and, ffter battle, you will receive items, but no experience.