Each criterion should be about 250 words long in general. However, this may be dependent on circumstances such as the position for which you are applying. It is recommended that you write more than one cover letter because there may be times when you want to focus more attention on specific aspects of your background. It is recommended to write your letter on official stationery or using professional email templates. This shows that you take your job search seriously and have respect for the process. It also gives you an advantage over candidates who use their personal email accounts for correspondence. In your letter, you need to explain what skills you possess that are relevant to the position. Focus on these skills without copying and pasting from elsewhere in your application. Try to come up with some original examples that show how you have used these skills in previous jobs. You can also mention any other achievements that are important to the company. You must also include information about yourself. Give a brief overview of your career so far and describe any experiences that you believe are relevant to the position. For example, if the position requires working with children, then mention any experience that you have had working with young people.