my experience

Why do you care so much about other people’s eyes?
Why do you always compare others in terms of life, study and appearance?

When I went to Auckland, my friends, who is from chill asked to me.
I didn’t answer this reason also I could’t admit this things also I had to think about this topic. (we don't talk like this in English, you don't usually use also in the way u use とか　in Japanese, anyway I don't quite understand what you wanted to say ;) )

I have older brother who is cheerful and kind and so (I would use 'very' in written language, 'so' sounds ok in sopoken though, if you want to emphasise) popular. When I was a child, I was very shy, quiet and reserved.Therfore my family and friends prefered my brother.I was really frustrated.
I thougt If that was too hard for you, work hard  and thoughen up.

I did four things. First, I took (up) a diet and I changed my appearance. Second(ly) I put everything I had into getting the club done (I don't understand this unfortunately) in order to become a manager. Third(ly), my grades improved. Fourth, I forced myself to change my character (attitude is a more appropriate word ;) ). I was able to change into cheerful and funny (person).
Therefore I was able to change everything. But there is still a wide gap between how they perceive me ?. I suffed (this word does not exist, maybe suffered ?) and I noticed this is not mine (I don't understand this sentence).  
In Japan there are so many people in the same stituation.

生活がもっと幸せだといいです ! 頑張ってください！