Do you feel like you're constantly setting limits and trying to enforce them in your home? Give yourself (and your kiddos) a break by choosing what "fights" you're going to fight. Allowing your child to experience some autonomy will go a long way in easing tensions between parent and child.
Application: Make a list of values or expectations that are musts for you. Practice letting go of things that are not on that list. For example, you may choose to let your child pick their own outfit for school, but stand your ground on the no hitting rule.