When you write an informal letter, you should use:
*Begins with "dear", "hi" or "hello"
*Refers to reason for writing
*Uses simple, short sentences
*Ends with "best wishes", "write soon"
*Ends with a signature
Hi! How's it going? Thanks for your e-mail. Sounds like it's going very well with your restaurant.
Well, we going to go university in a few days for the final exam. I can't believe how quickly the summer holidays went.
There are a new girl in my class this year and she is really nice. She is from new zeland, and is very good on pastry.
Talking of cooking, reminds me I have a chicken on the oven, I'd better go now.