The inverted pyramid or triangle structure is used in newspaper journalism. In this style the facts appear in descending order of importance. That’s because often the editor will cut paragraphs from the bottom of the story, if it needs to be cut to fit in the available space.

Some A to Z basic rules

A is for Accuracy. Get complete information, complete identification (designation/title) and complete names.
Z is for zeroing in immediately on the story you have to tell. Your article must sustain interest from beginning to end. If it doesn't, cut it down and change it until it does.

Four don'ts
1.    Don't write fancy prose or use fancy words when simple ones will suffice. Avoid jargon.
2.    Don't pad your story to make it longer than necessary. Keep it short.
3.    Don't write unsupported opinions or claims. Stick to facts.
4.    Don't be surprised if an editor rewrites your story. That's an editor's job.

The five W's and H

A news story should answer:
•    Who?
•    What?
•    Why?
•    When?
•    Where?
•    How?
If any of these elements is missing, the story is not complete.

Lead sentences

A long, overloaded lead sentence can be as objectionable as one that misses the main point entirely.
Do not try to answer all 5 W's and the H in the first sentence. Determine which are most important and emphasise one element in the lead, or opening, sentence.

Paragraphs

Make paragraphs short – newspaper style is usually one sentence to a paragraph. Write so that whole paragraphs can be removed without destroying the sense of the article.
Follow the inverted triangle principle and arrange paragraphs in the order of their importance.
Avoid starting paragraphs with "the," "a," "it," or "there."

Sentences

Do not pack too many ideas into any one sentence. Be especially careful of the lead.
Do not start a sentence with the same word with which the preceding sentence ended.
Keep sentences short while also varying their length.

Words

Use precise words. Make wording compact. Select each word for maximum effect.
Use adjectives sparingly. Strong nouns and active verbs seldom need qualifiers.
Eliminate:
•    Propaganda
•    Editorial opinion
•    Superfluous vocabulary
In news stories, avoid both "fine flowery writing" and trite expressions.
Do not use an important or unusual word twice in the same sentence or too closely in the same paragraph.

In Summary  

Make sure information is attributed to a source that is an authority/expert on the subject.
Check copy for accuracy. Check names (double-check spelling). Check numbers (cross-check your figures).
Don’t add your opinion on things – that’s called editorialising. Keep "I" and "we" out of the story. Avoid inadvertent comment.
Don't use emotionally loaded words. Don’t close with a moral or exhortation--quote your source instead.
Put in details that readers need to know. Don't assume your readers know something.