I always remember and teach when rudder is applied. Thinking in this way might help you. There are only a couple times when rudder is required to keep the airplane coordinated.
1. When the bank is increasing or decreasing, to counteract adverse yaw.
2. When the airplane is climbing, to counteract the left turning tendencies
3. When the airplane is descending with a lot of power to counteract P-Factor.
That is it. All the other times, the airplane engineers have designed it so the airplane stays coordinated.

If you can remember that whenever you bank the airplane, you use "hand and foot" it will become much easier. Have your instructor show you adverse yaw and also practice dutch rolls to get the feeling of how to use both rudder and aileron.
