Quality
Be Truthful
- Do not say what you believe to be false
- Do not say that for which you lack adequate evidence.
Quantity
Make your contribution as informative as is required (for the current purposes of the exchange).
- Do not make your contribution more informative than is required.
Relation
Relevance
Manner
Be Clear
- Avoid obscurity of expression.
- Avoid ambiguity.
- Be brief (avoid verbosity).
- Be orderly.
This list is based on http://en.wikipedia.org/wiki/Gricean_maxims