Forgive others for their wrongs.
When we are wronged or hurt, we can choose to hurt the perpetrator, or we can choose to heal. If we choose to seek revenge, this negative cycle of harm continues. However, if we choose to break that cycle and heal by forgiving the other person and moving on, we can bypass feelings of resentment, anger, hostility, and hatred that will only keep us from achieving happiness.
However, keep in mind that you can and should seek justice for wrongs that have been done to you. More importantly, you should not allow yourself to stay in a toxic situation in the name of forgiveness.