One important quality is being a good role model. Swearing, throwing things while ranting, arguing with the spouse in front of the children are some of the things parents do that affect their children's behavior. This will only encourage children to express their anger through negative means (such as throwing tantrums). When parents correct them, they will only get confused as what they see differs with what the parents preach.
Parents should also be understanding to raise their kids successfully. They should understand their children's needs and how to meet them as they go through different milestones. Parents should have empathy when disciplining their children. They have to consider that the environment, personality, fears, and peers affect their children's actions. Instead of scolding them immediately, parents should first understand the reason behind their mistakes.
Of course, no parents are perfect. Love can remedy all those imperfection. As long as children feel loved, despite the shortcomings of their environment, they will still grow up to be loving and caring adults.