For a police officer job position, you need the training, certifications, psychology exams and other tests completed. But in the cover letter, you can set yourself apart by emphasizing high profile cases such as homicides or even large drug busts. It may also be helpful if you have been productive. For example, maybe you average 100 DUI arrests per year with a 99% conviction rate. This type of quantified achievement lets the employer know you are dedicated to getting DUI convictions and that you know how to make the arrests properly.