My first lesson is be your true self, everyone is a unique and special and cannot be replaced and those who don't like you true self are not right for you.
The second lesson I have learned is that it will pass no matter how bad things get, I have seen my fair share of struggles in this lifetime with a little bit of faith and time you can get pass things.
The third lesson is asking for help when you need it is not a sign of weakness everybody need help at sometime in their lives and someone else can see the problem with a different view point so may be they can see something that you can not.
The forth lesson is that it's our struggles and scars of the past that make us how we are, I know for a fact that I would be a completely different person if I had never experienced even one of the struggles I have gone through.
The fifth lesson is that beings positive brings about positivity and negativity bring negative so adopt a positive attitude and try not to let people get you down.
My last lesson is that you can't please everyone so don't try to just try to be the best possible person you can be and the people who truly count will you be by your side and there will be people who dislike You for no apparent reason that is their problem not yours.