My advice for avoiding spelling mistakes in essay wring:
To those students who enjoy chatting on phones via WhatsApp, facebook email and any other electronic means, care must be taken, as you write, avoid shortcuts and auto-suggestion on keypads.
So try as possible to write accurately otherwise, it may affect your mechanical accuracy when writing an essay.

WASSCE Formal Letter Writing
First of all, a candidate should be able to identify whether a letter is formal or informal.

A letter written to someone you are familiar with, such as a parent, uncle, aunt, friend, brother, father’s friend etc. is an informal letter.
While a letter to your school principal, assemblyman head of your community etc. is a formal letter.

Formal letters are written in a professional way. The followings are the format for WASSCE exams.

Steps To Writing A Formal Letter:

Writer’s address
this is your address. You should write it at the top right-hand side. Put a comma ( , ) at the end of each line except the name of the city which must be ended with a full stop ( . ). See example at the section of ‘Date” below.

Date
the date should come below your address. The month must be written in word, and a full stop ( . ) should come at the end. The following is a complete address including the “Date”:

Labone Senior High School,
P.O. Box 233,
Accra.
10th October, 2018.

Recipient’s address
write the recipient’s address, starting with the designation of the recipient below your ‘Address and its Date’ but on the left-hand side. A comma should be added at the end of each line and a full stop at the last line. The following is an example of a recipient address:

Ministry of Education,
P.O. Box 23321,
Accra.

Salutation or greeting
the salutation is the greeting which comes after the recipient’s address and must be formal. Must put a comma ( , ) e.g. ” Dear Sir, Dear Madam, ”

Title or heading
The heading must be written in ‘CAPITAL LETTERS’ below the salutation.

Introduction or first paragraph
The first paragraph is an introduction which comes after the capitalized “Title”.
Here you are required to just state the purpose of writing the letter.

Body
body is the additional paragraphs after the introduction.
NB: i. write three or four paragraphs and link them together. Here are some transition words and phrases to link your paragraphs with: ” first and foremost, similarly, moreover, however, finally, likewise, in addition, “.
ii. write short sentences

Conclusion or last paragraph
the last paragraph is the conclusion of the letter. Summarise the whole purpose of writing the letter, including the action you want the recipient to take, in one paragraph.

Subscription
Write this at the right-hand side below the last paragraph followed by a comma ( , ) e.g:

Yours faithfully,

Writer’s signature
sign your signature at the right-hand side below the subscription

Writer’s name
write your full name below your signature at the right-hand side followed by a full stop ( . )

Goodluck!

Source: https://www.mywschool.com/wassce-how-to-write-formal-letter/