You always want to be as professional as possible in every step of your job search — and this includes your resume.
Everyone hates having to write a resume but that is no excuse to rush through it. So once you’ve finally forced yourself to actually sit down and create one, be sure to take your new (or revised) resume and: run spell check on it and proofread it a half a dozen times — AND then have at least two other people proofread it to see if they can find any errors.