No how should not be used for anyway.

No place should be written as nowhere.

None should be treated as a singular.

Not, like neither, must be followed by the correlative nor, e. g., "Not for wealth nor for fame did he strive."

Not ... but to express a negative is a double negative and therefore should not be used, e. g., "I have not had but one meal to-day."

Nothing like and nowhere near should not be used for not nearly.

O should be used for the vocative and without punctuation.

Oh should be used for the ejaculation and should be followed by a comma or an exclamation point.

Obligate should not be used for oblige.

Observe should not be used for say.