Perhaps one of the most neglected phases of letter writing is planning. Let’s face it, you have to know what you’re writing about and who you’re writing to before you start writing. Planning avoids miscommunication or ill-worded letters and get your point through.

Here are steps in planning that letter:

1. Determine the purpose of your letter

   Why are you writing the letter? Having an unclear purpose will only lead to a fuzzy letter that will not get a message through. So you better know . It’s sometimes best to state your purpose in a clear sentence.

2. Know your reader

   Who will read it? Is it for the boss? Subordinate? Client? Knowing who will help you choose the right tone and words. Remember that letters should read as if you’re directly talking to them.

3. Choose the thoughts to be included

   If you are responding to a query, simply answer the questions posed by your reader. If you’re the one initiating contact, anticipate what questions your reader may have and “answer” them in your letter.

4. Collect supporting facts
   To enhance your credibility as author, include facts to support the thoughts that you have. Determine if you need to attach other materials like tables, charts, picture and other supports.

Source: Business Writing