Learn different commands in battle. You will automatically run forward while you can use multiple buttons that execute different moves. You can hold down the sword button to attack instead of tapping it repeatedly. You can also use the shield button that will allow you stop running. You can also throw your shield to hit all enemies with it. Your allies each have one special move assigned to a button.
Cards
Sacrifice your least important cards. This is the best source of experience to boost the level of your other cards. Although you can gain experience after battles, feeding lower tier cards is better. You can do this five times to power-up a card. You can also do this with equipment cards. Feed low tier equipment to your stronger or preferred equipment that will be kept over time.