The correct way to use chopsticks is to hold the pair in the hollow between the thumb and forefinger of your fork hand. The one closest to your body should rest on the first joint of the ring finger and stay relatively immobile. Hold the other one with the forefinger and middle finger, which manipulate it like pincers to pick up the food. The strength applied by the fingers should vary with the things to be taken hold of. The skill to pick up, with speed and dexterity, small things like beans and peanuts and slippery things like slices of preserved eggs can only come from practice and coordinated action of the fingers.
Incidentally, using chopsticks has a great deal in common with wielding a brush to write Chinese characters. Those who write a good hand, some scholars have observed, are invariably those who handle the chopsticks correctly. One holds the writing brush basically in the same way as one would the moving chopsticks and, while writing, one must achieve coordination in the movement of the shoulder, arm, wrist and fingers in order to write well.
Westerners are often impressed with the cleverness of the Chinese hand that makes embroideries and clay sculptures with such consummate skill. Since you will stay in China for more than 10 days, you are strongly suggested that you learn how to use chopsticks while eating your meals with a spoon at the very beginning.