Research thoroughly the job responsibilities of the academic research position before you write your cover letter. In order to appeal to the hiring committee, your cover letter must show that your particular skills and experiences meet the demands of the position. You should note if, outside of the expected research duties, you are expected to perform other additional services for the department or university. For example, you will need to know if you will be required to mentor any graduate students or post-doctoral fellows so that you can briefly discuss your previous mentoring and teaching experience.
Write a brief overview of your academic experiences and education in the first paragraph after your greeting. This typically includes relevant biographical details, your dissertation research, awards and fellowships, teaching experience, and other related experiences. You want to demonstrate in this first paragraph that you are a strong overall candidate for this position.
Order the following paragraphs of your cover letter depending on the requirements of the academic research position. If the job announcement mentions that the department is seeking a candidate with a strong publishing record, the next paragraph should focus on your published work in recent prestigious academic journals. Subsequent paragraphs will then detail your experience in relation to the other requirements of the position.
Mention any professional correspondences you may have with professors in the department you are applying to and, more broadly, colleagues in your specialized field. Because professors typically specialize in small "niche" areas, there is a good chance that someone on the hiring committee may know the individual you correspond with and can seek that person out for a personal reference.
Close the cover letter by briefly reiterating why you are a strong candidate for the academic research position. Offer to send any addition material (such as syllabi of courses taught, peer reviews, and so on) relevant to the position that was not requested in the job posting.