The cover letter is an intimidating thing to write. I freely admit that it is the hardest part about a job application- it is for me, too, and I've written dozens of cover letters and read hundreds of them. The basics of what you need to do aren't that hard to grasp, but it can be very hard to write something that covers those basics well and still feels authentic. However, it is worth taking the time to really get the cover letter right. As @SteveB mentioned in the comments of my post of writing a resume, a good cover letter can rescue an otherwise mediocre application.
A bad cover letter, on the other hand, can completely sink your chances for a the job. Don't freak out, though. When I say "bad cover letter," I am thinking about the ones that say they are interesting in a different field than mine, or the one memorable one I received that talked about how the candidate had a "God-given talent for (specific job function)" and how he would profoundly improve our company's chances for success if we could convince him to work for us. This was from someone who was just graduating from college. We all had a chuckle and set his application aside.
These are easy mistakes to avoid. Most cover letters are not bad, but they're not good. They don't really hurt your chances, but they don't help them.
So, what should you do to write a good cover letter? To me, there are three basic requirements for a good cover letter:
- Convey the right information
- Clear, concise writing
- Proper grammar
Convey the right information
The point of a cover letter is to summarize how your skills and experience match the key skills in the job posting. You need to do the work of mapping your skills to the skills the hiring manager has stated that he or she wants. Use the keywords from the job ad! Don't make the hiring manager do the work of making the mapping, and don't make her guess if your "aqueous container construction" is the same thing as the "underwater basketweaving experience" requested in her posting, even if you come from a lab that strongly prefers the "aqueous container construction" designation.
You should not laboriously map every single skill in the job posting to your background. Instead, pick the key skills. This is a chance to demonstrate that you truly understand the position and what they key skills for that position might be. If you read a job posting and can't figure out what the key skills are, you should try to do more research into that field. Yes, it is probably a very poorly written job posting. Deal with that, and work around it to submit a solid application, anyway.
If there is a significant hole in your background with respect to the posting, don't pretend it isn't there and think the hiring manager won't notice. The hiring manager is almost certainly scanning cover letters and resumes specifically looking for the key skills- if yours is missing too many, it will just be skipped. Instead, think hard about your background and experience, and try to identify something that indicates an aptitude for learning the missing skill. For instance, let's say the job description calls for experience in underwater basket weaving, coordinated diving techniques, and reed selection. You have underwater basket weaving and coordinated diving techniques nailed, but lack direct experience in reed selection. However, you collaborated on a project in which you worked with the reed selection group. You can say something like this:
"While I do not have direct experience in reed selection, I collaborated closely with the reed selection department on a basket diversification initiative at Baskets University, which gave me exposure to the fundamental properties that must be considered when selecting reeds for an underwater basketweaving project."
Bonus points if you can offer to put the hiring manager in touch with the person with whom you collaborated, and that person will say you are wonderful. (This is a heavily anonymized real life example, in which I hired someone who had absolutely no experience in one of the key areas of the job. The cover letter sold me on the candidate, and the hire worked out beautifully.)
Only do this if you actually find something that truly indicates an aptitude! Do not contort your experience into unnatural configurations to try to make a connection that just isn't there. If you do not have anything at all relevant in your background and the missing skill is one of the key aspects of the job, say something like this:
"While I have not yet gained direct experience in reed selection, I look forward to the chance to grow in this area."
If the missing skill is just one in a long list of desired technical skills, I would just not mention it.
Other things to include in a cover letter, if relevant are:
An explanation of any unusual gaps in your work experience, particularly if they are recent. This can be very brief. If you have a gap due to child rearing or elder care, simply state that. If this is your first job on your way back in and you can point to something you've done to stay current or refresh your skills, do so. I would not necessarily explain a gap between college and grad school, unless it is unusually long (more than a year or so), but I can't think of any examples of this from my hiring experience, so I honestly don't know what the best advice is here. However, if you are doing a postdoc now and had a gap between grad school and postdoc, I'd explain that.
If you are changing fields, indicate that you are interested in the new field. You would not believe the number of cover letters I have received that not only don't do this, but actually mention a long interest in some other field. Don't do that. But also don't assume that your interest in my field is obvious. Maybe you've just fundamentally misunderstood my job posting. How am I to know if you don't tell me? This can be a single sentence, such as: "I am interested in the chance to apply my knowledge of basket types to applications in underwater basketweaving." This indicates that you have read and understood that my job is NOT in the history and classification of basket types, and that you are at least willing to claim an interest in my field beyond the potential to collect a paycheck. If your only interest in my field is to collect a paycheck, it is best to keep that to yourself.
Clear, concise writing
Most corporate jobs involve a lot of writing. If nothing else, you are likely to be writing a lot of emails. No one willingly signs up for a future of reading someone else's tortured prose. You want your cover letter to convince the hiring manager that you can write well. This does not mean that your writing must be on par with that of a great novelist. It just means that you must be able to structure your paragraphs and sentences logically and convey your message concisely.
You don't want to write a long, rambling cover letter, but it also must be long enough to convey all of the necessary information. I aim for 3 paragraphs of 3-4 sentences each. That is not a rule- it is just a guideline. If you can cover all of the important information in less space, that's great.
I cannot emphasize enough the fact that your cover letter must be constructed logically. If I cannot follow your letter without serious effort, I am probably not going to hire you.
Since the cover letter functions a bit as a writing sample, I am not a huge fan of the advice I sometimes see to make a table mapping skills in the job description to specific items in your background. However, I don't think I'd rule out a candidate for doing this, so if you are a very weak writer, you can consider that method. I think it would be better to get some writing advice, instead, but perhaps if you are applying for a very technical job, the writing sample aspect is less important.
I am reasonably forgiving of a typo or two in the resume and cover letter, but a true grammar mistake is usually a large mark against the candidate. I am more forgiving in this regard if the candidate is not a native English speaker, but even then, I will not overlook a large number of mistakes. Find a native speaker to proofread your writing. If you do not have a friend who will do this, look for paid help. (Corollary: if you are a native English speaker, help your colleagues out when asked. It is good karma for when you travel to their country and attempt to communicate by shouting "DO YOU SPEAK ENGLISH???" at people.)
The reason I so strongly dislike grammar mistakes in cover letters is simple: it shows a lack of attention to detail and precision, and those are usually things I need the person I am hiring to have. Writing a cover letter and resume is a good time to get in touch with your inner perfectionist.
Those are the basic points.
There is one additional consideration I'd like to mention: when you apply to multiple jobs at a single company, the hiring managers can almost certainly see this, even if the company is quite large. The resume tracking systems companies use makes this obvious.
I don't see anything inherently wrong in applying for a couple of closely related jobs. However, in this case, you will need to work extra hard on your cover letter to make sure that it is appropriate for all of the jobs to which you apply. In some cases, the resume management system will only store one. Even if you can submit more than one, they sometimes get mixed up. And even if they don't get mixed up, the hiring manager might read both. Therefore, I'd recommend writing a slightly more generic cover letter that can fit both jobs.
Better yet, though, would be to try to network your way to someone at the company who can help you figure out which job is the best fit for you, and apply to that one and only that one. If the people inside the company think a different job is more appropriate for you, they will probably consider you for it anyway. (Really! Hiring is hard. We don't care how we come across the resume for our dream candidate- we're just thankful we found it.)
Another thing to keep in mind is that preferences for cover letter styles and content might vary a bit between industries, so if you can find someone in the industry you are targeting to review your cover letter and resume, that is likely to be very helpful. However, I have received advice very similar to what I put in this post at the outplacement services I've gone to after being laid off (this is often part of the lay off package), and those services were not focused on my industry- so I suspect that a large part of my advice here will be applicable to other industries.
That's all I can think of right now. Other hiring managers out there- what do you think? Job candidates- what questions do you have that I have missed?