Write a Yawner
By now you know you need to be serious and professional when crafting a cover letter, but it is possible to take this sentiment too far. Taking every standard cover letter line you've ever heard, and folding it into one dry -- but serious! -- letter, is just one way. Maybe hiring specialists won't fault you for taking this approach, but if your cover letter is filled with clichéd lines and is just plain boring, it's not going to score you big points, either. In fact, it'll probably be tossed before being completely read.
Just as you learned in grammar school that it's not good to start a report with an opener like, "My paper is on Abraham Lincoln," don't start off your cover letter with lines like, "As you can see on my enclosed resume," or "I just graduated with a Bachelor's Degree in accounting," or "I'm applying for the job I saw on your Web site." You need to grab the hiring manager's attention, and those kinds of lines aren't going to do it. Compose a powerful opening sentence that summarizes the skills and experience you'd bring to the job so the manager is compelled to want to know more about you [source: Creighton University].