Basically Twains message in this article is to obey your parents. He doesn't go right out and say "kids you should all obey your parents", instead he uses reverse psychology on us because he knows we always want to do the total opposite of what we're told to do.
In "Advice to Youth" Mark's ridiculing kids by giving them wrongful advice telling them that they should pay attention to their parents when "they're around", meaning when they're not around do as you please . Another example of how he's giving wrongful advice to us kids is by telling us to "practice lying" that way we'll be good at it and won't get caught. In my opinion, this piece is successful because it shows a perfect example of satire. Then again it might not be successful because some kids might take his bad advice into consideration and actually do all he suggests to do.