This will be a post itself later!
I'd be very interested in that :D
My advice for 18 y/o self would be similar to yours, friends & family & experiences first, it's not because you chose to go on a vacation for one week that you're gonna miss out on success, making sure to manage your levels of stress and balancing work & life is as important as work itself.
Also: no sleeping less is not a time saver, you may gain 2 hours of day by sleeping 6 hours but you'll lose them in productivity anyways
Great advice Howo!:D