If your step-daughter is like most teens, she may appear preoccupied with herself as she compares each action, thought and desire with those of her peers or an idealized adult. The development of an identity separate from the family requires a great deal of inward focus.
While she may be extra difficult in an attempt to push you out of her life, your persistence can help her learn to love not only you, but a difficult boss or in-law in her future. It often takes many years for teens to love and trust a new parent enough to accept her guidance.
Your spouse can help you figure out a set of expectations that allow your step-daughter to participate in family life in a way that makes sense to her based on past rules while helping her learn to accept and respect your needs.
She contributes to eHow in the areas of parenting, child development, language and social skill development and the importance of play. For example, if she's used to eating whenever she's hungry and you're trying to establish family dinners, work with your spouse to compromise so that she eats with you on certain nights or sits with the family even if she's already eaten.
However, if you grit your teeth and bear it, you aren't doing your step-daughter any favors. If your step-daughter is like most teens, she may appear preoccupied with herself as she compares each action, thought and desire with those of her peers or an idealized adult.
Work with your spouse to make these expectations clear along with the consequences for violating them.