First notebook entry: Introducing myself

I‘m a college student in the third year.
My major is teaching Chinese as the second language,so I think my English must be good then I will not let foreigners misunderstand my words,so I can do a better job when I am a teacher.

My major is teaching Chinese as a second language.  I want to improve my English so that I can be a better teacher, and so that foreingers will not misunderstand my words. 

I just wrote the words above after the tips,well,introducing myself...

My hobbies.I like singing,reading,watching TV series like The Big Bang Theory,I do like shopping or chatting with friends and families.Or something other girls like,such as bling bling shiny things,cute pets,and fashionable things.

My hobbies are singing, reading, and watching TV series like the Big Bang Theory.  I also like shopping and chatting with my friends and family. I also like things that other girls like, such as bling bling, shiny things, cute pets and fashionable things.

My characters.I had cheerful temper when I was a little girl.While there happened some things recent years,I become a sensitive person,I am cautious to pretect myself from the strangers sometimes.But I'm still a happy girl if I am staying with my old friends and families.

(Usually we would say "my personality",  instead of  "my character".)

When I was a little girl I was cheerful and carefree, however some things happened in recent years and I have become a sensitive person.  I am cautious to protect myself from strangers.  When I'm with my friends and family, I'm still happy and carefree.

Well,I think so many people are like this,that's not special.But I cannot stand a friend's betray.Some people will forgive the guys when they come back and apologize,but I can't.I will be unhappy to talk with the guy or just see the guy,there is an obstacle between the two of us,as I see it.
It's like a nature.But I think I'm not mature enough to forgive someone.

I think many people are like this, so it's nothing special.  I cannot stand a friends betrayal.  Some girls can forgive guys when they come back and apologize, but I can't.  I will feel unhappy talking to him or just seeing him.  I feel as if there is an obstacle between the two of us.

It's natural, but I don't think I'm mature enough to forgive someone.

Should I introduce my hight,weight or blood type?well,I don't think so.And I think I might write it as a diary,not the one the system asked.'Cause it's my first time here,so...I might be better next. (￣︶￣)↗

Great job!  I can understand your meaning, I just re-worded your entry to make it flow better.  Also, don't forget to put a space after punctuation marks.