Everyone has an opinion on cover letters, and mine isn’t so much different from The Career Doctor. Randall recently blogged:
Always err on the side of being brief, so no more than one page, and really about four paragraphs total. If it’s an email cover letter, it should be even shorter…. The first paragraph must engage the reader. Make it dynamic. Make it weave the reader into the rest of the letter. Don’t waste it with some boring formulaic sentence. The second and third paragraphs give specific details that highlight your qualifications and your fit with the position and the organization; if possible, use some of the employers own words here. Your last paragraph should thank the reader and request an interview. You should also say you plan to follow-up the letter at a later date — you must be proactive.
That’s a pretty good start, though I would say that having a “dynamic” opening paragraph isn’t nearly as important as simply contextualizing the rest of the letter in a brief, competent way. Be direct, if dynamic isn’t possible. It’s the heart of the letter that needs to be dynamic.