It helps if you have some little signal that turns you from Mom to Teacher Mom, such as ringing a bell at the start and end of each day. When the bell rings, the rules change. Socialization is one issue which has to be addressed. Several siblings help, since family socialization is a good training ground. It helps to live in a neighborhood with other children, who should be frequent visitors to your home.
Children also benefit from attending church, joining clubs or taking lessons with other children.
If you feel uncomfortable with any aspect of your child's curriculum, consider hiring a tutor or putting the child into a community class. Remember though, that socialization is just learning to get along with people. Any people will do. Most homeschoolers are very well socialized according to studies, so it's not as big a problem as you expect. The socialization children get at school is not necessarily a positive thing.