DO:

DO find out the name and title of the person who makes hiring
decisions and write to her/him directly if at all possible.

DO address the letter to “Dear Sir or Madame” if you absolutely can’t find out the name of the person you are writing to.

DO compose each letter individually for each specific job or
company.

DO be as specific as possible.

DO keep it to one page, especially for entry-level positions.

DO use plain white paper

DO have a date on your letter

DO indicate if you are attaching or enclosing other documents

DO NOT:

DO NOT address your letter "To Whom it May Concern".

DO NOT address your letter to “Dear Sir” unless you are 110% sure you are writing to a man.

DO NOT use “Mrs.” or “Miss”, always use “Ms.”

DO NOT write one general letter and send it to several companies

DO NOT begin each sentence with “I”. Describe what you will contribute to the organization, not what you will gain from the position.

DO NOT sign a letter in bright colors such as red, pink or purple.

DO NOT attempt to use a creative format, unless your job is 100%
based on creativity.