I've worked in HR so I can give you some practical tips.
First, your cover letter is not what gets you through the door. If HR does a pre-screening of all the candidatures it receives (which can number in the hundreds), it's looking for essential qualifications. That means diplomas, relevant experience, solid references from the past 3 years, etc. Your CV is much more critical here.
That being said, if your application gets past this initial stage, your cover letter can be quite important in convincing whoever's doing the hiring that you're worth paying attention to.
For privacy reasons I can't give you any examples of successful letters, but I can tell you some of their commonalities.
First, they are generally long. It has been largely recommended by guidance counselors everywhere to keep it to 3 short and sweet paragraphs which briefly detail why you are good for the job. In my experience, this is not that helpful because it prevents you from going into any detail about your qualifications or previous experience and ends up repeating or cannibalizing your CV. I would say 3/4 of a page of text is standard. More than that seems long-winded and less seems like you don't have enough to say.
Second, they are specific. The best letters clearly pay attention to two things: what the company/org does and what the job listing describes as the role of the new hire. Good letters explain, in detail, why the applicant is both a good fit for the organization and the specific functions of the position available. I've seen far too many letters that are clearly just form letters with the names changed and which say nothing specific aside from "I believe I could be a great asset to your company." If you have to say that, it's clear your'e not. Instead, describe what distinguishes you from the rest and it will be implied that you're a great asset.
Never mention things like "I would like this opportunity to develop my skills further" or "I lack xxx experience but I am a quick learner." These are red flags. Your letter should be confident without being arrogant. Do not talk about your special abilities like an overzealous parent describing how talented your child is; instead, imply them by describing the concrete things you've accomplished.
It goes without saying that the format must be professional and there can be no spelling or grammatical errors.
That's about it. I'll be honest, it's not the most important part of an application. In my opinion, the interview trumps all. If you interview well, you can do better than someone with an amazing CV but who doesn't know how to sell themselves in person. Nevertheless, a good letter can set you apart, and having someone remember you as "the guy with the great cover letter" is a major asset.
I'm asking a serious question here and so was r...
