The person who I want to talk( il manque la préposition du verbe 'to talk...' qu'il faudra mettre avant le relatif, le relatif lui est en fonction complement du nom donc il manque un petit quelque chose)  isn't like very famous actors,singers or sportsmen, I have chosen a person who I know( temps à revoir, c'est une action qui dure et qui a commencé dans le passé) for a very very long time. Because I think that we can't really know how are famous people( how est ici relatif donc le verbe est mal placé) , how they lives (conj), how they think, ... Simply : What character they have( question à revoir)  ? and so I can't describe a person if I don't really know her. The person of my choice have( conjugaison)  a big part on my heart, is everytime here for me and played a major role in my life

This person who I want to present is beside me since my birth. He is one of the most important persons for me, It's my brother.
He understand (conjugaison) me everytime, and together we laugh a lot.He is an extraordinary man.

He helped ( les temps avec He sont à revoir, vous parlez au présent) me when I have problems,he cheered me when I'm not sure,he bucked me up when I'm sad. And even if before it wasn't very beautiful between us because he didn't like me because I'm younger than him and so my parents tend to me more (sens? il manque quelque chose) , now it's really the contrary, he has done a lot of strivings (mal dit)  to be an exceptionnal person in my life, since that, the relationship between us is very strong and nobody or nothing could destroy it. I realized thanks to this relationship that family represents the most important relationship in the world. My brother gave me values as perseverance,courage,optimism,hope so he play the role of adviser. He listened to me, I can count on him that's very important for me.

Also, I can considered him as a keeper, I feel safe with him and he defend (conjugaison)  me when somebody wound (conjugaison) me. He is very social and my friends who know him like him too. Certain ( calque du français) would have a brother like me because they think that he is sole.

My brother plays (il faut mettre au preterit)  and still plays a major role in my life. First he is my life's advisor, he is an outstanding brother, he is generous, and it's him who permited me to become how( erreur de relatif)  I am now. I can just add that he is my model. So I identify myself to him, I love him and I don't want to lose him for nothing in the world.
Voilà!
Amicalement
sébastien