DO's and DON'Ts

DOs

Make sure your letter is addressed to the right person at the right address
Check all spelling, grammar and punctuation (including titles and addresses)
Include your contact details in the letter
Write your letter on good quality paper that matches your CV
Customise your letter to target your potential employer
Use bullet points if you need to, it can make the letter easier and quicker to read
Include a proper introduction and ending
State how you would like this application to be followed up

DON'Ts

Send your letter to "Sir/Madam"
Write reams. Your letter should be short, concise and to the point; you don't need to duplicate all the information on your CV, just pick out the highlights
Use long words simply to impress. This won't give an accurate representation of yourself and you may misuse a word