To support an only child's social and emotional development, parents and caregivers can ensure they have plenty of opportunities to play and interact with other children. They can also help a child learn and practice how to engage appropriately with other children, for example, teaching how to share, take turns, and help others.
Other tips for social development include:
supporting a child's emotional identification, regulation, and expression
providing encouragement and praise to a child
setting fair and consistent boundaries and routines
actively engaging in quality interactions with a child every day