Hey, I didn't say it was easy, just that it was necessary. They have to interact with adults without your advantage of maturity and experience. Which is why so many predators have success on the Internet. Aggression in children is seldom a good thing. On the other hand, assertiveness just may save his or her life.
Predators are kind of like lightning.
They strike fast and unexpected, preferring to take the path of least resistance. They look for signs of timidness in their victims. Teach your child to go through life, being aware for signs of danger and discuss plans for dealing with that danger. Remember, nothing instills confidence, like knowledge. A prepared child, is a confident child.