"Without looking at the ball, how can you tell if you are applying enough rudder when rolling into a turn?" - George Y.
“The seat of your pants will give a good indication whether you are in coordinated flight. Any side force against the seat cushion will indicate that you are out of coordination, whether it be toward the inside or outside of the turn.
We use rudder to correct for adverse yaw, which is caused by drag from the down aileron. Adverse yaw is the tendency of the nose to initially move in the opposite direction of the turn as the airplane rolls into its bank.
If the proper amount of rudder is used when rolling into the turn, the nose should stay in the same place on the horizon and then begin to move in the direction of the turn. If the nose initially moves in the opposite direction of the turn, not enough rudder was used.”