news writing method

It depends largely on their credibility. The higher the reputation of the paper, the more care (and better editing staff) they will employ.

No, in fact, journalists often use conventions of their own which would not be approved in the style manuals issued in the United States. Headlines in particular are notorious for playing games with the language to attract attention, and the entertainment industry rag, Variety, is famous for it's "catchy" headlines. For example, if a Michael Moore film was doing badly at the box office, Variety might have a headline which read "Moore's Poor Door."

The content of journalistic articles is largely grammatically correct, but newsmen and -women rarely admit errors in language, due to a hubris about being the "keepers of the flame" for society.

I myself somtimes come across some clear errors, though I'm not very good in English grammar rules.

As Setanta said, the rules of English grammer are pretty much ignored when it comes to headlines. However, the body of the text should, strictly speaking, be accurate, but human error is far from unknown.