Formal letters to the editor are often written in response to something you have heard or read. There are many reasons for writing (e.g. to complain, to offer your opinion, etc). It is essential, when writing such letters, that the register is appropriate for the target reader (e.g. a newspaper/magazine editor). In other words, the tone of the letter should be respectful, and the person receiving the letter should have a clear idea of the reason you are writing.
A letter to the editor should contain:
An introduction, in which the reason for writing is clearly stated. In other words, it is necessary to state what you are responding to (e.g. an article which you found offensive, an advertisement that you object to, a television programme that you felt was inaccurate, etc).
A main body, in which the task is covered according to the instructions given. Each point is presented and analysed in different paragraphs.
We start each paragraph with a topic sentence introducing the topic, then we write examples/justifications to support each point (supporting sentences).
A conclusion, in which you summarise your opinion. The conclusion can also contain demand/recommendation/etc concerning any action you would like them to take.
You can use this graphic organiser to plan what you are going to say, and how you are going to organise it (ideas, linking words, wow language).