Step-by-step explanation:
When you are writing a letter you should include your full address at first, the date and address of your friend.
Then you can start by writing the body of the letter.
Dear friend John,
I am writing to you because I want to tell you news about my new school at this moment. I was thinking of transferring to your school because there are some things that I do not really like here.
First of all, there are no enough sports activities like in your school. Second, it is really far away from my home. I have no friends and there are so many old teachers that are rigorous. I like your school better.
Yours,
Mark M.