Before I thought these rules were enough:
Let your children know they can talk to you about anything.
Educate them about sex.
Tell them they will never get in trouble for telling the truth.
Tell them if someone tells them a “secret” then tells them they can’t tell their parents that is precisely the secret they should tell as soon as possible.
Never leave them with someone you don’t trust.
If they can talk, they will tell you if something happens…
Now I know these rules were woefully inadequate. Abusers, predators, capitalize on the innocence of children at all cost.
New rule (an addendum): never leave your child alone with someone you do not trust completely.
Narrows the field considerably.