Not accepting gifts off of strangers (sometimes because it might be poisoned, sometimes because they are using it to lure you to be kidnapped)
Inappropriate touching. Usually, they say that all touching you don't like is unacceptable, but touching your private parts makes that person "bad" or "sick in their mind", however some crank it Up to Eleven and list all touching you don't like (such as hugs if you're not a hugger) makes the person bad. Other times they don't give you specifics and tell the viewers to be wary of "all touching you don't like". Quite often with the private parts, they make exceptions for parents who need to wash your private parts or
Not going into a stranger's vehicle or house, or not going anywhere with them.
(If this time and universe has the Internet) not to give out your personal info online.
Not keeping secrets.
Certain things not to say. This involves not telling strangers your name or address. Some people go Up to Eleven and say "Don't talk to strangers at all" or "Don't even give strangers directions." This could backfire if the child wants or needs to talk to a police officer or shop keeper.
Who do they warn about?:
Sometimes, all strangers.
Sometimes everyone who does something bad. This is realistic, but can lead to Paranoia Fuel if they say that "anyone could be bad"
Sometimes, all strangers except police.
Sometimes, anyone who does anything "scary". Which is a bit ambiguous as some scary things (like Halloween) can be fun and some things might scare some people, but not others.
What do they tell the viewers to do?
Often they recommend saying no and going away to tell someone, but they sometimes don't specify who.
They often stress that it's okay to do things like say "no", bite, hit, kick, push, yell, or tell people what to do when dealing with these bad people.
They sometimes say to tell a parent or an adult you trust.