Forgiving someone who has injured one involves two parties - the injured and the perpetrator.
Circumstances may be such that the injury was an accident and the perpetrator horrified and asking what they can do to make amends. In this case the path to forgiveness is already paved with possibilities, and the injured has but to specify what is required to make amends and the two parties will begin to heal each other. Circumstances may be such that the injury was an accident but the perpetrator in denial. Nothing has happened, and even if it did it wasn't their fault. In this case forgiving the injury must take place on separate paths, with the injured coming to terms with the accident as just that - an accident. The perpetrator has already forgiven himself, as he wasn't there and there is nothing to forgive. Circumstances may also be such that the injury was deliberate, but was a result of a disagreement, a fight, and fault lies all around. One was pushed beyond his limits and lashed out. One was steadily tortured until a dark mood overtook him. In these cases forgiveness usually progresses rapidly, as both parties are clearly cognizant of the underlying currents and the shared responsibility for what has happened. Tears, hugs, and a resolve to be more careful in the future.
Forgiveness is most difficult where the injury is deliberate and no fault lies in the one injured - a true victim, an innocent. And thus the perpetrator has savaged the injured for sport, for a power trip, or to simply gratify themselves at the expense of another. In these cases forgiveness is inappropriate, and is not the issue. In these cases the injured should be concentrating not on forgiveness, but on defense, and after ending the assaults on changing the circumstances that allowed the injury in the first place. Does your criminal justice system forgive the sadistic murderer and say to the victim - the problem is yours as you have not learned to forgive?