Encourage socializing
Create opportunaties for play with other children.

Teach how to deal with anger.
Help the child stay in control when she/he is frustrated. Offer some ways like breathing slowly, counting to twenty, etc.

Encourage healthy self-expression.
Teach the child to express feelings through talking, writing, drawing, not violence.

Teach conflict resolution skills
like stop fighting, think of a solution, get help if the solution does not work out.

Help rebuild self-esteem
Encourage the child to believe that he/she deserves to be loved. Remind that, he/ she is capable of many great things. Praise the child often for the small achievements.