things we wished we had learned at the time
When I was young and 'old people' gave me advise Did I listen ? Did I take notice ? Did I adhere to the advise ?
Fuck no.

Once when I was 17 an elderly gentleman friend told me how quickly the years have flown and that from 17 - 82 it had just gone ... and I remember the occasion as if it was yesterday and thinking - ' Silly old fool, I'm only 17.' and that was 59 years ago now and he was quite correct, it has flown.
There are lots of things older people said to us decades ago that we wish later on, that maybe we should have listened, as they were right...
Education:
Get a good education. It is never wasted. Helps you get a good job.
Get a good training / apprenticeship :
Sets you up for a job for life.
Here are some jobs for life that gain you respect:-
Bankers - Policeman - Teachers - Priests - Politicians - were trusted and admired. ( Not any more.)
Read lots of good books :- Any kind of education is good and you never know if and when you might need some esoteric knowledge that will help you. Believe in something :-
Does not need to be in God or Budha or anything at all - as long as you believe in yourself.
Be a good person :-
There are enough assholes out there, don't become one of them.
Be good to your parents :- As we grown older we realise the sacrifices made for us by our parents. Be thankful and considerate, they may be odd balls and they may say and do strange things sometimes, but most parents mean well and do not mean to be a bad parent - no one does - there are just things that can get in the way - it's called LIFE.

Listen - Learn to listen and not talk all the time :- Some may say I have not taken this one on board yet.. ha ha .. there is always time.
Pension:
Pay into a pension as young as you can start one as the benefits when you are old will amaze, but at the time you think - WTF it's decades away yet.
Save for a Rainy Day :- Do we hell.
Look after your health and your teeth.
The NHS is based from cradle to grave but not for your teeth.
Look after the pennies and the £ will look after themselves.
Save save Save - Anything, as you never know what is round the corner - look at the Covid 19 year we have had. Without savings - milions of people are now reliant on Food Banks and the generosity of strangers because they did not save for the rainy day. Rely on Number One only : - Trust no one : - Good advise any time in your life as there will always be those who take advantage and screw you.
Only lend what you are prepared to loose. And never lend to friends - it ruins relationships.
Give it your best :-
If your best is not good enough, at least you can stand tall in the fact that you did - actually - give it your best. If you don't, then take responsibility for why you were fired / lost out / left behind / ignored etc. as unless you give 100% - you are responsible for the outcome.
Eat your Five a Day :-
Athough not hard when I was a child, as we eat our veg as we were told to - No picky eaters back in the 60's, you eat what you were given or went without. Who had heard of Gluten Free or Vegan ?
If a stranger tries to talk to you :-
RUN AWAY.
Be respectful to your elders:-
As they are wise and wonderful - except with learning we realise many are just fucked up messes and we need to stay away.