You probably take pains with your résumé. You may even take pains with your cover letters. But chances are you don’t take pains with your writing sample. The vast majority of students I know act as if writing samples don’t matter. That’s a mistake.
Writing samples matter a great deal when employers rank their candidates. After completing call-back interviews, I winnow down my finalists by reading writing samples. I assign letter grades, using pluses and minuses, and drop those with the lowest marks.

We have lawyers working at my office who, without the boost they received from an outstanding writing sample, wouldn’t have ranked high enough to receive an offer. Because they turned out to be some of the best all-around lawyers we have, I know we make better hiring decisions by evaluating writing samples.

Employers treat your writing sample as an example of your best work, so you should make it flawless. No rule says you have to give it to employers with the same errors or problems it had when you turned it in to your professor or supervising lawyer.

Ask someone to review your work. If you’ve established some rapport with a legal writing instructor, he or she may be a good person to ask to look over your writing sample. If you’ve been fortunate enough to clerk for a skilled and friendly practitioner, you might ask that person to review it as well.