One of the common problems I've observed among several résumés in my Résumé Remedy group is the improper use of tenses. It may seem obvious to use the present tense when detailing a current job, but résumé writers are constantly using the past tense or seem to misunderstand how to properly use tenses in general.
You don't need your own professional editor on call to clean up your tense issues — instead, read your résumé out loud so you know what it sounds like to the employer who will be reading it. You're likely to catch several mistakes with your own ear. Rule of thumb: if you have to add words when reading it aloud for it to make sense, then something is probably amiss.