The following tips will help you get better results from this site's French translation tool and machine translation tools in general.
The ideal unit that the translation tool works best with is a complete, coherent sentence, or a passage consisting of several sentences.
Sometimes, it's tempting to use the translation tool for part of a sentence. For example, you're reading a bit of French which you basically understand, but there's one small part of a sentence that you need help with. So you put the small part of the sentence into the translation tool, hoping it will tell you the meaning of just that small part of the sentence.
The problem with this is that the translation tool is largely trained on whole sentences and the translation of the phrase in question may depend on the surrounding sentence. If you input only a small part of a sentence and don't get a meaningful result, try putting the whole sentence.
If you do enter a phrase, try to avoid ending it in a "dangling" linking word such as the preposition de (or of in English). Leaving a dangling word will sometimes work, but this will sometimes prevent the translator from finding an appropriate translation.
If you're copying the text from somewhere, try and make sure you keep the correct spelling and accents. Machine translators are not very tolerant of misspelt words, particularly as the misspelling could actually be another word.
In many informal computing contexts, it's common not to bother putting accents on French text, particularly if your keyboard doesn't have accent keys. This often isn't a problem. A fluent speaker of French can easily understand French written without accents and ambiguities are rare, particularly in a passage of text. Indeed, this site's dictionary allows you to omit accents when looking up words: if words exist with and without the accent, the dictionary simply gives both entries.
For a machine translation system, it's a different story. Omitting an accent can completely change the category of a word. For example, an -é on the end of a French word often indicates the equivalent of English -ed (past participle), whereas -e without the accent could be a present tense verb form. The circumflex accent distinguishes between the preposition sur ("on") and the adjective sûr ("safe", "sure").
If you're not sure how to type accents, then see our guide to typing accents.
One of the most common causes of mistranslations or failed translations is absent punctuation in the source text. Be careful about the following:
This site's translation tool includes a filter that can correct for a few common punctuation problems (such as cest instead of c'est or missing spaces after punctuation) but you are likely to achieve better results by properly punctuating the source text.
If a word has a large number of meanings but a less ambigous synonym is available that expresses your particular meaning is available, it may be preferable to use the synonym.