It may start with your 2-year-old clandestinely pinching his newborn sister...but sibling rivalry can last for years when it goes unchecked. When they're small, squabbles about toys, personal space and competitions for affection seem to spark rivalry. When a toy dispute arises, resist the urge to intervene every time. Siblings who try to solve conflicts peacefully among themselves tend to bicker less than those who constantly run to mom or dad, setting up the "bad kid/tattletale" dynamic. Ask younger children to make requests of their siblings nicely: "How do we ask Brother for a turn?" Reinforcing their relationship - using phrasing that includes "your brother" or "your sister" - can help diffuse anger and tension. Establish what is shared and what is off-limits to each sibling, and an egg timer might help when it comes to taking turns watching TV or playing with toys. If disputes arise over what TV shows or movies to watch, then blame the TV instead of taking sides with one child or the other.
Simply turn off the TV and tell the kids that it needs a time out. As they get older, their fights may get uglier and more physical, including hitting and name-calling. Don't make one child the villain in those situations - sometimes the hitter or name-caller has been provoked and teased at length and finally lashes out. In this case, both children are in the wrong. And in every case, the hitter should be punished - no negotiations. Remember that accidents do happen when kids are playing physical games, but reinforce that there should be a magic word - such as "stop" that should keep play from getting to an uncomfortable physical level. To prevent blowups, make an effort to spend at least 15 minutes of one-on-one time with each child, every day. Give them the words to express frustration so that they don't resort to verbal abuse, and establish boundaries and consequences for breaching those boundaries.