What is a letter to the editor?

This is a letter you write to the newspaper commenting on a current news story being addressed by the paper. The letter may criticise some aspects of the paper’s coverage or bring additional context to a particular story. It may also respond to a previously published letter. Letters to the editor appear on the Opinion / Editorial (op-ed) pages and are one of the most highly read sections of the paper.

What dos it do?
Like an editorial piece, a letter to the editor can allow your comments to be presented with minimal mediation or interpretation by the paper itself. This requires you to keep the letter short.
 
When to use it?
Use it when you want to comment on a current story and/or its coverage without mediation and an op-ed piece isn’t warranted (because you don’t have enough to say on the matter, because you don’t think they’ll print an op/ed piece for you, or because you don’t have enough time to research or write one).

Important things about writing a letter
•    Keep it short. Notice how long the published letters to the editor usually are and try to stay within those boundaries to avoid someone cutting your comments.
•    Criticise objectively. It you must criticise the paper itself, do it in a calm and objective manner, backing up any claims you make with facts and concrete examples.
•    Try to ensure a human face. People respond best to human stories, accounts and comments.
•    Sign the letter. Make sure you sign the letter and provide the paper with your name and address; otherwise they will usually not even consider publishing it.
•    Don’t overdo it. People who write more than one letter a month are dismissed as crackpots.