I read cover letters every day. What’s wrong with most of them?
1. They’re too long. If conventional wisdom says employers don’t have time to read resumes, how will they have time to ready windy cover letters?
2. They simply repeat details from the resume. The purpose of the cover letter is to introduce you and your resume. Let the resume speak for itself.
3. They talk too much about the employer and how wonderful the employer is. Employers know their company. They want to know who you are. More importantly, they want to know why they should invest time in interviewing you.
Remember the function of a cover letter: Write something that makes the employer want to read your resume – and meet you.