| “ | With more than 1 million articles in English, I think we should continue to turn our attention away from growth, and towards quality. I think the quality of our work should be something we're all very deeply passionate about. | ” |
| — Jimbo Wales, Opening Plenary of Wikimania 2006 (transcript) | ||
Good research is 
the most vital component
But, no original research, please. Original research includes editors' personal views, political opinions, and any personal analysis or synthesis of published material that appears to advance a position the editor may hold. That is, any facts, opinions, interpretations, definitions, and arguments published by Wikipedia must already have been published by a reliable publication in relation to the topic of the article. See this example for more details.
(See: WP:NOR)
Let the facts speak for themselves
Be careful not to err too far on the side of not upsetting editors by leaving unsourced information in articles for too long, or at all in the case of information about living people. Jimmy Wales has said of this: "I can NOT emphasize this enough. There seems to be a terrible bias among some editors that some sort of random speculative 'I heard it somewhere' pseudo information is to be tagged with a 'needs a cite' tag. Wrong. It should be removed, aggressively, unless it can be sourced. This is true of all information, but it is particularly true of negative information about living persons."
(See: WP:VERIFY)
Substantiate statements that may look biased
Think ahead. Try to imagine whether or not people might doubt what you wrote, or need more information about it. Supporting what is written by referring to clear and reliable sources will add credibility to your contribution.
(See: WP:CITE)
Improvement is 
better than argument
When the notability of your article is challenged, don't sit pretty like a duck. Go for the Heymann Standard. Improve the article beyond doubt.
(See: WP:NN)
Having a brain is alright
And, yes, it's okay to use your brain. Be bold. Take the right step. Just take care that the step is really right.
(See: WP:BOLD)