Introvert kids don't usually express themselves and parents have to understand themselves what's running in their kid's mind. It is very important for kids to learn from their early age to speak out their mind and open up with their friends and family. It will make them expressive and they won't hesitate in mixing up with the new people and environment.
Apart from school, parents also need to put some efforts to make sure that their kids are confident enough to open up about their thoughts.
Understand his/her nature
There's nothing unusual about being introvert. Some people just don't easily share their thoughts easily with others. In the case of kids, they find it difficult to open up with their teachers or friends and sometimes even parents. What parents least can do about this is, they should understand their kid and should not force him/her to suddenly involve into new people or the environment.
Start with his/her hobby
Introvert kids are more passionate about their hobbies. Sometimes they find it a way to express themselves. So, encourage your kid to pursue his/her passion. It will help him/her gain self-confidence and as soon as s/he'll find anyone with the similar interest, s/he starts finding new friends. Extracurricular activities at school are a good option to start.
Help them putting their fear out
Your kid might hesitate to do something or to deal with a new person. You can make it easy for him/her. Encourage them to fight with their fear and point out even a small achievement from past as an example that they have the capability to win over their fears and this time also they can do that. Encourage your kid to move out of the four walls of the house and go outdoor and play with kids.
Make a day special for your kids !!
The impact of a father over his kids !!!