Have a clear aim in mind before you start writing, and make sure that you gear everything you write towards that aim alone.
Keep things as simple as possible by using language that is clear and familiar.
Keep sentences and paragraphs short.
Avoid long, pompous words and phrases when there is a short simple alternative (especially avoid the words: utilise, facilitate, endeavour, necessitate, render).
Avoid unnecessary words, clichés and legal words.
Avoid repetition.
Use active rather than passive style.
Do not turn verbs into nouns.
Use personal rather than impersonal style.
Always refer to the same ‘thing’ in exactly the same way.
Use examples and analogies before introducing abstract concepts.
Write informative (rather than descriptive) abstracts.