You should take care of the following things
1. Parents must discipline themselves first.
2. Instructions must be communicated in positive manner.
3. The child must be capable to correctly receive, understand and apply the instructions.
The bigger part of discipline is reward, encouragement, talking, listening, respecting, understanding and much more.
First try to convince him by telling what good things he has done. Make him feel you really love him and care for him. After that slowly show the mistakes he did.
It' very bad to be rude at the very first time. Be patient, you are on the right way.
Child Discipline
Learning how to effectively discipline your child is an important skill for all parents. Children have to be taught discipline. They are not born with it. You must be consistent and must train your child to obey through diligent and careful discipline and precise instruction. The rules cannot be changed from day to day. They have to be the same each and every day. Discipline is not the same as punishment. Instead, discipline has to do more with teaching.
Following are the goals of discipline: To teach a child right from wrong, how to respect the rights of others, which behaviors are acceptable and which are not; To set limits and correct misbehavior with a goal of helping to develop a child who feels secure and loved, is self-confident, self-disciplined and knows how to control his impulses; To raise a child who does not get overly frustrated with the normal stresses of everyday life.
Firmly enforce boundaries indicating what behavior is acceptable and what is not.
Children are keen observers. When they see you doing things a certain way, they are going to imitate you.