In standard English, neither on its own is used with a singular verb: Do not attempt to bring livestock or plant material into the country; neither is permitted. But in colloquial English, it is completely acceptable to use a plural verb: Neither are permitted. Similarly when neither is followed by of, it is common to use a plural verb: Neither of her parents are alive, but a singular verb is more appropriate for formal writing: Neither of her parents is alive.
When it is followed by nor, the verb agrees with the noun or pronoun that comes after the nor. If this is singular, the verb is singular: Neither I nor your father was told about it. But if it is plural, the verb is plural: Neither the French nor the Italians have qualified for the finals.
If one noun or pronoun refers to a male person and the other to a female person, it is permissible to use a plural verb and plural pronouns, in order to avoid the invidious 'he': Neither Beth nor Tim have collected their tickets.
When you use neither ... nor, it is preferable to put both the neither and the nor immediately in front of the parts of the sentence they refer to. She will eat neither meat nor dairy products is more acceptable than: She will neither eat meat nor dairy products.
When neither is a pronoun, it refers only to two things or people. For three or more things or people, use none. But when it is a conjunction, it is perfectly acceptable to use it for three or more things or people: The prisoners were allowed neither food, sleep nor washing facilities for 48 hours.