Older readers (over 21), what is the best advice you would give someone younger?

i'm 31 years old. There are many good answer to this question.. some of my advices are written for others persons already, so i'll say 2 that i want to add or emphasize:
1- Do what you want to do. But i'm not speaking only about dreams, i'm talking about all your choices. Dont let others provoke you; dont listen to all the advices/suggestion/etc you receive from people, i mean..yes listen to what they have to say if you want but dont make decisions based on them without thinking about the consequences...because the one who will suffer the consequences are you and you (and sometimes persons important to you).. so think about the bad and the good points and only make a choice when u are ok with it. Some people give advice just to see what'll happen.. i learned it the hard way, from a person i considered a friend, she gave me some advice in love matters, and i did it, because she was so persistent that just to dont hear her anymore i did it thinking "well she isnt wrong, what can happen?"...and the next day she told me "wow u really did it? i never in my life would do it".. and who suffered the consequences? she? no no...only me :( so make the choices that make you feel ok with yourself.
2- Dont make any decision when a feeling is overwhelming, if it is a bad feeling (sad, angry, etc..) because it's difficult to think through any matter.

im sorry if i make any mistake writting, i'm not very good with english ^^U