The part of the world where I come from, women are most times blamed for rape done to them, so the first way I would help a rape victim is by not judging or blaming them for the act. It is never the victim's fault and ALWAYS the perpetrator's as they should be held accountable for their actions.
Next, I would give them a listening ear if they are willing to talk and proceed to get them professional help so they can heal completely from the gory incident.