Always read through notes on the last lesson, and the lesson ahead before you get in the plane. It's free on the ground to just go through a circuit in your head, in the air you're paying £2 a minute or more.
Stay focused, and keep looking forward. Studying the ground exams alongside flight training makes them more relevant, and therefore more interesting, but you need to get them out of the way. You don't want to end up ready for a test, but still with 3 or 4 exams to cover.
Have fun, and take something positive away from every flight.