Every Parent should be the model for their children coz everything the parents do is right in the eyes of their children. The parents should mold and train them in the right path where they should go and if it is necessary, discipline their children and let them understand that what they are doing is wrong and should be corrected. The wrongdoing of the children should not be tolerated so that they will not grow delinquent.
Being a "good" parent is a tough thing to do and it will be done 24/7 and the discipline that the parent should impose will start from themselves.