Many resumes that I see contain superlatives, such as "excellent," "outstanding" and so on. Used sparingly and strategically, these are generally fine as readers understand that a resume is first and foremost a personal marketing tool and that you are naturally trying to promote yourself. However, once you begin using superlatives repeatedly or to the point where readers question the relative lack of evidence to support their use, you run the risk of alienating your audience and, worse, having your resume tossed onto the proverbial reject pile.
When considering the use of superlatives, a solid way to earn your readers’ respect and to attract their interest in you as a candidate is to make sure you not only use these sorts of words sparingly but also include outcomes or accomplishments (from either your work history and/or volunteer experiences) to support or reinforce them. By doing so, you will be providing evidence to support their use and as a result you will take your resume to a higher level of credibility and professionalism. Another way to further reinforce your credibility and support the use of superlatives is to include short testimonials from supervisors, instructors or other individuals who can attest to your abilities, experience and overall performance.
Sometimes in preparing resumes, one can get too close to the document and end up overusing superlatives. Taking care to insert outcomes where applicable is a good way to prevent this and to increase the positive impact of your resume in general. Another tried-and-true way to prevent overusing superlatives is to put your resume away for three days after generating an initial draft and then to give it a good look afterward—you’ll likely be surprised at the increased rigor you’ll bring in getting your content into tip-top shape.