Details of situation
________: give previous history of event or your background or experience.
Conclusion
________: The conclusion has to wrap up the letter.
You must be familiar with the format of an informal letter
salutation (Dear/Dearest..),introduction, body (maybe two paragraphs), conclusion, signature (With Love/Yours Truly..)
In the example above, you could say
Ive been dying to tell you about this circus that came to town last Friday
Body
This is the actual content of your letter
Conclusion
The conclusion has to wrap up the letter
Eg
shortly after that/later/that afternoon/after dinner etc
Salutations and Signatures
use either of this format
Introduction
Dive straight into the point
Body
This can be divided into two paragraphs
Details of situation
give previous history of event or your background or experience
Further development
Give further support to your claim or request
Conclusion
Say what you wish to happen next