A business letter should not only communicate your message; it should also reflect the professionalism that is expected of a correspondence of similar kind.
To present information that bears the appropriate attitude for business letters, your writing should be confident. Your letter should clearly express your trust in your message and ideas. If you don’t trust them yourself, there’s no reason for anyone else to. Avoid the use of words that express doubt and probability. Instead use specific and concrete words that express certainty.
Giving your recipient appropriate respect is mandatory. The language and tone of your letter should be courteous. Avoid using words that are hostile or offensive. You may have better grasp over the subject, but avoid condescension. Establishing your authority over the topic is not the purpose of a business letter.
Business writing is expected to carry a certain air. It should befit the respect professionals in a certain field have for one another. You should communicate at the level your recipient is used to. Inability to do so will result in losing many potential clients.
Use gender-neutral terms and language that avoid exclusion of any groups. It is not always easy and your language may at times lean towards keeping people out. Use a good thesaurus to find inclusive alternatives instead.
Be brief. Keep your letters concise and to the point. Business men are busy. Don’t expect them to have the time or patience to read long winding stories. State the purpose of your writing in the beginning itself. Avoid unnecessary details, but don’t forget to include the necessary ones. Your recipient should get your message as soon they read the letter. They should not have to write back asking clarification