Chew on this, job-hunters: According to a Creighton University survey of 600 hiring managers and human resources personnel, more than 85 percent of U.S. employers feel cover letters are important or very important -- yet they only have time to give them a 15-second glance. That means when you sit down to craft your cover letter, you've got to do two things: Write a strongly worded piece that will quickly grab the hiring manager's attention, and make sure it doesn't include any glaring errors or unprofessional components that will cause him or her to quickly chuck it in the circular file, no matter how compelling its contents. Sounds like quite the challenge. But don't worry -- it's actually easier than you think. When drafting your next cover letter, just don't do any of the following 10 things.