|Reading cover letters on the computer creates different expectations of the applicants than applications you submit in hard copies.|
I have read many cover letters for academic jobs, including those for non-tenure line teaching jobs and academic administrative jobs. I'd like to share a few tips. Some of them will seem very obvious. Others I think you can only know when you have been on the hiring side of things.
1. Don't use bullet points in your cover letter. In an academic setting you have to show that you can put your thoughts together into cohesive paragraphs. In my experience, bullet points in a cover letter usually indicate poor writing and lazy thinking. Use judiciously, if at all.
2. Name your documents wisely. Many, maybe most, academic job searches are conducted online nowadays. Some things that never would have mattered before, now matter. The search committee will see how you have named your documents. This file--"applicationfinalversion.doc"--gives a bad impression. "Cover letter," is better because it tells me exactly what to expect when I open that document. "Cover Letter Abbott" is even better because it helps me put all the pieces together--type of document and from whom--before I even open the document.
3. Create and upload one pdf. This is more of an idea for you to toy around with than a firm to-do. Reading all the documents from all the applicants for a search (and there are usually many, maybe even hundreds) requires a lot of clicks. If you can save me the bother of opening up a lot of separate documents, I will appreciate it. However, I do see the advantage of the focus that separate files brings. If at all possible, you might upload everything as separate files and then create a combined file that you name "All Application Materials Abbott" and upload.
4. Make your cover letter do the search committee's work for them. In other words, a cover letter that maps neatly over the job ad makes the search committee's work easier. Let me explain. The search committee is going to be using a review criteria because the law stipulates that you have to compare everyone in the same manner and that you have to follow the criteria that you stated in your job ad. So the search committee is going to read your letter and at the same time be looking at a form and ticking off some boxes or assigning a rating (1, 2, 3) alongside each criteria. If your cover letter jumps all over the place or leaves gaps, then the committee members will need to spend extra time looking in other documents to try to fill in the gaps. Why make them do that? For example, if the job ad says that you need five years experience teaching at the college level, a simple phrase like, "In my ten years of teaching at the University of X,..." makes ticking off that box so much easier. (However, this does not mean that search committee members don't read all your materials and won't catch any misrepresentations of the facts. They do and they will.)
5. Use two pages. In the corporate world, the advice says that cover letters should never exceed one page. In the academic world, you need more than that. Up to two pages is fine--as long as you are using that space to map out your qualifications against the job ad and using specific examples to showcase your expertise.
I hope this information will be helpful to some of you!
Update: This piece offers specific wording in a long list of points that should be included in a cover letter. It advocates writing a cover letter of two and a half pages. I said to write two pages, and that was mostly a warning against people who think that a cover letter should only be one page. As a frequent reader of cover letters, I still think that two pages is enough and all I want to see/read.