Take several knives from small to large and hold one in your hand. Place the other hand on your wrist and check where can you reach with the knife when held. Change your position and height of the hand (overhead, shoulder height, at the back, fully extended etcetera) and change the way and height of the holding hand. If you can do the same with a partner and do it also when you are sitting down and getting up. It is a good drill to get away from holds and paying attention to the whole. Relax your eyes and face and let the solution come to you.