I've never worked as a translator but I want to be one. I speak Arabic (mother tongue), Persian (almost fluent), English (intermediate) and just started learning French one week ago. To be a translator doesn't mean you must know many languages. If you're fluent in only two that will be fine. Actually I am seriously thinking of abandoning French for more concentrating on English. Knowing two languages at a high level is better than knowing 4 at a low level.
Yes, translation is a hard job that means speaking two languages or more doesn't make us translators. We should practice a lot before our translations become professional. Also when you feel your languages reached a quite good level you should pick and focus on one specialisation ex medical, financial, legal, technical, literature....etc.
You can work in a company or at home but some companies require a degree in translation. If you work at home you should work hard to find your clients.