It's always tempting to go big and try and smash your opponent's resistance straight away, but that can often mean that after your first big attack, you're left with nothing to do for a couple of turns while you draw new cards, place them on the board, and wait for them to attack. Try and make sure you've always got something to do on your next turn. That can mean holding back, but it can also mean playing smart, and ensuring that the turns when you need to draw cards are the time when your big attacks are set to happen.