Explain the class rules on the first day of school. Tell preschoolers that they must follow their teachers' directions, and saying "no" to a teacher is unacceptable.
Use positive language to try to change the child's behavior. For instance, if he is yelling during circle time, you can say calmly: "Please use a quiet voice," rather than "Stop yelling." If a child is kicking a wall or punching a table, say in a stern but tranquil manner: "Please keep your hands and feet to yourself," instead of "Don't do that." Phrasing your directions this way is less harsh; also, it tells the child how he should behave, rather than how he should not behave. Remind him at this time of what the consequences will be if he continues to disobey the rules.
Remove him from the situation if he continues to be defiant and he ignores your instruction. You should remove him after only one warning, since focusing on his negative behavior and talking to him over and over will only give him the attention he is seeking. Ask a teacher to take his hand gently and lead him to a quiet corner or out of the classroom, if possible.
Talk to him about his defiance. If he is resisting following a classroom rule, ask him: "Why do you think we have that rule?" and "What would happen if no one followed that rule?" Explain that it is important to listen to the teacher and other adults because that is how students stay safe, learn and have fun. Ask him what is bothering him and making him feel angry, since there may be a larger issue that is upsetting him.
Put a teacher or classroom volunteer in charge of assisting the child during the times when he is often defiant. If he always struggles with others during lunch time, ask an adult to sit next to him and help facilitate conversations between the child and others.
Praise the child when he follows directions, demonstrates good behavior and acts accordingly. Say: "Thank you for listening to your teachers and picking up those blocks!" He will feel proud of himself, and he should realize that he feels better when he is attracting positive attention, rather than negative attention.