In the standfirst I will make a fairly obvious pun about the subject matter before posing an inane question I have no intention of really answering: is this an important scientific finding?
In this paragraph I will state the main claim that the research makes, making appropriate use of "scare quotes" to ensure that it's clear that I have no opinion about this research whatsoever.
In this paragraph I will briefly (because no paragraph should be more than one line) state which existing scientific ideas this new research "challenges".
If the research is about a potential cure, or a solution to a problem, this paragraph will describe how it will raise hopes for a group of sufferers or victims.
This paragraph elaborates on the claim, adding weasel-words like "the scientists say" to shift responsibility for establishing the likely truth or accuracy of the research findings on to absolutely anybody else but me, the journalist.
In this paragraph I will state in which journal the research will be published. I won't provide a link because either a) the concept of adding links to web pages is alien to the editors, b) I can't be bothered, or c) the journal inexplicably set the embargo on the press release to expire before the paper was actually published.
<snip>
Complete piece at the Guardian:
http://www.guardian.co.uk/science/the-lay-scientist/2010/sep/24/1