Nurture the preschooler's natural personality traits. Only when a child is comfortable being herself will she open up to her peers.
Make a quite space in the classroom and at home for the preschooler to engage in quite, independent activities. An introverted child will expend great amounts of energy during social interaction and needs time alone to rest and recharge his batteries. In school, assign a quiet reading nook or craft corner; at home, allow him to retreat to his room for rest after a long day of school or a play date.
Arrive early to social gatherings, such as birthday parties and play dates. Do the same on the first day of preschool. A child who is shy in any way will feel more comfortable if she feels that children are coming to join her in play, instead of her trying to join groups of children that have already formed.
Organize play dates at the child's own house. In a one-on-one situation with another child, a shy or introverted preschooler will feel more comfortable coming out of his shell on his own turf.
Pair children up during group outings or class trips. An introverted child will have a single partner to focus on, rather than putting pressure on her to break into a group of friends. This is also an effective safety measure for all children
Encourage the child to interact with adults as often as possible. He should say, "Please" and "Thank you," order his own meals at restaurants and interact with vendors when paying for an item. Interactions with adults can seem more intimidating than those with peers and positive experiences speaking to adults will boost a preschooler's confidence.