EVEN SO, if the advice changes for the better the life of only ONE listener in a group then that is "a result" as Tom Barnaby would say.
Advice may also of course come under the heading of "the bleedin' obvious", but as far as that is concerned, I learned a nice expression years after leaving school which impressed me a lot:
There are many bits of advice one might give to a youngster, but one of my favourites is this.
Find some moral and/or interesting and if possible useful skill that you REALLY enjoy - and practise it until you are VERY GOOD AT IT: doing card tricks, guitar-playing, doing different accents and impressions, juggling, chess, painting, telling jokes and so on. Another idea is to become an expert on a few great historical figures or periods: Celtic Britain, the Norman invasion, Da Vinci, Faraday, Newton, JFK, Alexander the Great, Descartes - WHOEVER or WHATEVER INTERESTS you. At the right moment you will be able to do your party trick and/or play a full part in the discussion - AND impress people!
People are also impressed by someone who has shown the dedication to master a skill or field of knowledge.
NOBODY at WHS ever told me this directly, but the staff DID make an effort to enable us to try out as many different activities as possible: the unstated aim being to encourage us to follow our interests and deepen our knowledge of them. That is most obvious in the number of actors and musicians WHS turned out - but there were other areas of interest, too. THIS is a list of the clubs and societies that WHS boys could participate in.
One other really nice skill is to learn a few quotations you can slip into a conversation. Proverbs are fine, but almost everyone knows the usual ones. Quotations are a different matter. My WHS teachers didn't really push this point. We learned quotes from Shakespeare of course - and some lines of the most famous poets, but I think we missed out otherwise. In hindsight, we could have had a "Quotation of the week" from someone famous to discuss.
I love quotations, and have made a collection here: http://www.vervinomni.net/id/phil/def.htm
These are great minds speaking to us from the past.