A business letter is a personal commitment. Every sentence, sometimes even a word, is a business situation. Every business letter represents a book of legal situations. To write a good business letter, you need good business skills.
A good business letter:
The quickest way of achieving clarity in your correspondence is a simple layout. Design your letters to contain a lot of information in the headings.
Always use references in your standard layout. These, and a subject line, and quoting other people's references, will save any possible confusion. A simple macro will do this for you.
The physical text can also be a problem. Fonts should be 12 point standard business fonts (Helvetica, Arial, Times New Roman, Trebuchet MS, etc.) for easier reading. Some software, like blog software, just can't read some fonts. Usually they can read one of these fonts. Sending an email, it matters.
Body text layout
The other basic trick of layout is not to use masses of text. Lengthy paragraphs can be extremely hard to read. Having to wade through text isn't good for your readers, or for your business. Use smaller paragraphs, and break them up, to make the letter easier to access.
Body text, in addition to being easy to read, has to be laid out to separate the individual messages and subjects. It's counterproductive to create a letter where subjects are mixed in together.
You can use bullet points, separate paragraphs, and even single sentences, but the mixing of messages has to be avoided. The natural result of mixing subjects is for the reader to become confused and have to decipher the message.
Information quality: Checking what you're saying
Information quality is the primary content consideration. The basic rule is that 'If it isn't useful information, it shouldn't be in the letter'.
The best way to achieve good information quality is in the drafting stage. Find the problems in a letter before you send them to someone. Always ensure that a letter is checked prior to issue. Most real problems in correspondence are the result of information quality errors.
Never include any material which can be misinterpreted by the reader.
This is the basic criteria for every sentence and every word in your letter. If it can be misinterpreted it will, and that's where your information quality has to be fully operational. You may find yourself writing some very basic sentences, but it's a much better option than annoying a client.
Your letters not only have to be good, they have to look good. Courtesy, good professional standards, and accuracy are all very important. They dictate how your letter is viewed by the reader.
A well presented letter means good business. A messy letter full of obvious mistakes is a disaster in progress. Set a high standard for your letters and stick to it.
Always use plain language.
It's quite futile to write a letter nobody can read. Do not, ever, use text message spelling or internet slang. Unless you know the reader will understand the usage, don't use unduly technical language.
Just remember one thing: That letter is going out with your name on it.