The negation for verbs in French is composed of first the 'ne' particle (a global negation), and second one of several other words clarifying the negation's type:

ne (verb) pas = "not"
ne (verb) rien = "nothing"
ne (verb) personne = "nobody"
ne (verb) jamais = "never"
ne (verb) jamais rien = "never anything"
ne (verb) aucun(e) = "not any"
ne (verb) plus = "not any more, no longer or no more"
ne (verb) que = "only"
ne (verb) gu're = "not much, not any" (archaic)
ne (verb) point = "not, not at all" (mostly literary)

Placement of the Negation with simple verbs

Normally, the element 'ne' precedes the verb which is marked for tense. Therefore a simple verb is usually placed between the 'ne' particle and the characterizing part of the negation:

For instance:

* " Elle ne parle pas. " = "She does not talk."
* " Il ne voyage plus. " = "He does not travel anymore."

Note: 'ne' always comes before the object pronouns - me (myself), te (you), le (him/it), la(she/it), lui(him/her/it), nous (us):

* " Ils ne nous ?crivent plus. " = "They don't write to us any longer."

Elision of e: ne and n'

Similarly to other words terminating in a vowel in French, the e of the 'ne' particle is elided (condensed) when immediately coming before a word starting with a vowel (or with a silent 'h' then a vowel):

* " Ils n'hibernent pas. " = "They do not hibernate."

Position of the Negation with Compound Verbs

Compound verbs are compounded by the past participle of a verb [i.e. laiss? (left), touch? (touched), which remains unaltered in terms of tense] and an auxiliary (sustaining) verb such as avoir (have) and ?tre (be).

As it is the auxiliary verb which is marked for tense, it gets inserted between the first part of the structure, ne, and the second (qualifying) component of the negation:

* " Je ne suis pas encore parti. " = " I didn't leave yet."

There is an exception, still, when 'nulle part' (anywhere) and personne (no one) are used with compound tenses, these secondary negation particles come after the whole compound verb (and thus follow the same negation construction as that of simple verbs):

* " Elle n'a cru personne. " = "She didn't believe anybody."
* " Je n'ai vu mes parents nulle part. " = " I did not see my parents anywhere."

Ne..que (only) in compound tenses can take both locations, dependent on the intended meaning, as it is not strictly speaking a negation but an adverb:

* " Il n'a publi? qu'un livre. " = "He only published one book."
* " Nous avons parl? qu'? lui. " = "We talked only to him."

In fact, with 'ne ... que' the negation construction is not totally essential, as the same concept can be expressed positively with the word 'seulement' (only):

* " Il a seulement pay? 15 centimes. " = "He only paid 15 cents."

Spoken habits vs Written form

In conversational French it is normal to leave out the 'ne' completely in fast speech (but not in written format).

It is also usual in modern literary style to drop the 'pas' particle with the verbs vouloir (to want), savoir (to know) and pouvoir (to be able to).

Thus we have:

* " Je ne veux pas. " (correct)
* " Je veux pas. " (spoken)
* " Je ne veux. " (literary - equivalent to "I want not.")

How can I possibly recall of all this, you might say? A great deal of drilling will get you there. Native French speaking people don't even learn any of this but still practice it perfectly. So do you. But when you need to translate technical, financial or legal documents from English to French, I would recommend to hire the help of a professional translation company. It will save you time or difficulties and at the end is worth the investing. Practice would not get anybody there in years factually and automated solutions just don't cut it at all in such specialized subjects.