1) Put one chopstick between the palm and the base of the thumb, using the ring finger (the fourth finger) to support the lower part of the stick. With the thumb, squeeze the stick down while the ring finger pushes it up. The stick should be stationary and very stable.
2) Use the tips of the thumb, index and middle fingers to hold the other stick like a pen. Make sure the tips of the two sticks line up.
3) Pivot the upper stick up and down towards the stationary lower stick. With this motion one can pick up food of surprising size.
4) With enough practice, the two sticks function like a pair of pincers.