There are some points to be kept in mind...
1.Preparing to initiate a lesson, the teacher should realize that the child's attention should be focused on the object of study.Hence the teacher should clear the table of everything else and place on it only the material she wants to present to the class.

2. The teacher's role is only to show the students how to use the materials.The teacher should perform the exercise herself once.She should work carefully and exactly , using forethought, minimum movements and minimum words.
3. The teacher should have enthusiasm and interest in what she is doing. A cold and bored attitude will discourage the children from taking up the activity.The teacher should be able to rouse the students interest in repeating that activity.
4. The children can make two kinds of errors while doing the activity.
- The first error is the error when the child makes in working with a material like Building blocks -connecting one block over the other or spilling water on to the floor when pouring it from one container to another.These mistakes occur,because he child has not yet mastered coordination of will and motor.They can be corrected only by further development of the child, by repeated use of the material.The children learn from these errors and rectify it by themselves.The teacher needn't assist them in these class.
- The second type of error is due t a kind of ill will, or negligence on the part of the teachers.Here the child uses the material for purpose other that it is designed for.This may harm the material or the children.When the material is used wrongly so as t create confusion ,or for needs that it cannot satisfy, it is not really used.The result is waste of energy or uproar.This prevents the child from being able to concentrate and therefore from being able to grow and develop.
- In such cases the teachers has to assist the child in gentle or energetic ways, without ever screaming or hitting the child.There is no place for punishment,but for earnest words and good temper.
The teacher should be careful not to interrupt in their work or try not to correct his slight errors or stop them work working .
6. When children stops the activity of their own , the teacher needs to guide the children to put back everything in it's place and clear the workplace.
Once the children has been introduce to the exercises in the first classes and has already worked on it their own number of times,they will be able to distinguish the difference in the sense materials.
Now the teacher intervenes during the time the children performing the activity to give them exact names of the materials they are working with.This helps to increase their vocabulary and assist them to speak correctly.When the teacher gives them the names,She should pronounce each syllable exactly but without assuming a false manner of speaking.
Introduction of an object or a material can be divided into 3 periods.
First Period: The teacher gives the child the name of the object; "This is a Square."
Second Period: The teacher can ask the child to find the object after it is named for him: " Can you find the Square?".This way the teacher can test if the child can now recognize the object corresponding to the name.
Third Period: In the third period the child ha to remember the name corresponding to the object.Here the child is asked to name the object pointed to: "What is this?"( as the teacher points to the square).