Assalamu Alaikum.
I know I'm not old and wise yet (I suppose that means I'm young and stupid, lol), but if I had to give a piece of advice to the world, it would be to "ask for help". And I suppose, a part of being mature is swallowing one's pride, realising when we're most vulnerable and in need, and having the strength to reach out for aide. I personally have always had trouble with that and I still kinda do. I don't like bothering people or being needy or non-selfsufficient. So, when I learned that Allah (God) is actually waiting for us to ask him for anything and everything that is good from him and as often as we want, I was pretty surprised. Ever since I started making du'a consistently my life has been changing for the better now, in every way possible. Alhamdulillah.