How to deal with a child who just isn't very nice

I have two children (15M and 12F) and two Step-children (13F and 8F). I have been with their father for several years. Generally things are harmonious at home except for the 8F is just.. not very nice.The 8F step daughter tends to lash out and be unkind, difficult, and yells at the other children seemingly at random.Despite 8F's behavior, the other children are still pretty nice to her and are generally very nice to each other.Anyone else have experiences with mean children? via /r/Parenting https://ift.tt/2B0zaBs