If your chopstick technique is unreliable and you find yourself asking for a fork when in a restaurant it would be a good idea to practise at home.
Hold the chopsticks parallel in one hand. Your thumb and forefinger hold and manipulate the top stick. Your middle finger rests between the sticks, keeping the bottom stick held still. The top stick is manoeuvred by the thumb and forefinger to grip food and bring it to your mouth.
Place your chopsticks by the right-hand side of your plate when you are not using them; you may be provided with special rests. Never use chopsticks to pass food to people, and never use them to point at other people.