What is Mark Twain's central idea in "Advice to Youth"?I read a passage in his address and I do not understand Twain's point.

Is it not amazing that anyone would ask Mark Twain,
America's curmudgeon, to address a group of young girls?  As so cogently put on the site
listed below, it did, indeed, "turn the conventional moral lecture on its
head."

Yet, in his satire--as is usually the case with
satire--Twain does give some solid moral advice.  The main point is what the previous
poster has succinctly written, conventional wisdom is often hypocritical and phony: 
Getting up with the lark does not make one a better person, obeying one's parents simply
because they are the parents teaches nothing, the truth does not always prevail, and
guns do not always kill people.

If, however, one
understands Twain's satire, one realizes that he--perhaps more than many others--truly
believes in moral behavior, for he quips that he has not learned how to "practice this
gracious and beautiful art."  And art it is, not reality.  The perspicacious listener,
then, would have discerned this valuable lesson and long remembered it, as is usually
the case with satire.