Be realistic about the behavior you expect. Thirty years ago, a 1-year-old who scrambled off his mother's lap to join a party was surprisingly independent. Now a 1-year-old who won't join in is often called clingy. The current emphasis on babies' need for stimulation, along with the boom in group activities for toddlers and preschoolers, has pushed children's social development forward by about a year. That single year is a quarter of a 4-year-old's lifetime, and sadly, some children can't cope.
Children only become much more independent when their current need for dependence is satisfied. If your toddler is floundering, hitting other children, and behaving rudely at home, you may be seeing a sort of show-off pseudo-independence that really means "Help! I'm only just managing." Is your child getting enough attention (and downtime) when she's home? If she attends daycare, are there enough caregivers (one for every three or four toddlers)? The ratio of adults to kids is crucial to childcare quality. Is group play carefully supervised so children aren't expected to fight their own battles?
Make sure that neither you nor a caregiver is assuming your child's social understanding is greater than it really is. He knows "don't hit other children," but does he know what he should do with other children instead and how to do it? She knows "keep quiet and listen," but does she discover that if she listens to the teacher now, the teacher will eventually listen to her? He knows "wait in line," but does he understand that not pushing and shoving other kids ensures a turn for him as well as the other children?
Make the best use of your attention. Adult attention is the cause, the effect, and the principal agent of change in children's behavior. Unfortunately, parents don't always use this power to encourage "good" behavior and discourage "naughtiness." In fact, some parents get it the wrong way around. As long as children aren't doing anything tiresome, they're ignored. Only when they begin to feel lonely and neglected and start squabbling, interrupting, or reciting rude words do they get the "reward" of a parent's attention. (Think of the whining children who get candy at the supermarket and the well-behaved kids who don't.) If you're one of the many parents who fall into this trap, you're actually punishing your child for desirable behavior and rewarding the opposite. Try to spot and reverse this trend before your child discovers that attention-seeking always works in the end. Even if you can ignore the blackmail of a public tantrum, you can't ignore a child who plans to bite the baby.
Your child will only stop seeking attention with negative actions when she learns that she can get just as much -- and maybe more -- notice when she's nice. Making more overall time and attention available to your child may mean changing your hours, but changing how you use those hours may work too. Simple and obvious ideas sometimes work best. Calling ahead to tell your preschooler or older child you'll be home in 20 minutes can seem to take 20 minutes off the time you're not there. Switching off your cell phone and turning on the answering machine from the moment you walk in the door until your child is in bed -- and not checking your e-mail -- can help him feel you're not just there, you're there for him. Asking her to help you with tasks instead of putting on a video to keep her busy gives her that good message: "I want to be with you."