To start a career in translations, mastering one or several foreign languages is not enough. Obviously, you need training, but also certification to become an accredited translator/interpreter.
First of all, you must be accredited as a translator/interpreter based on a study or course certificate.
You should also choose a field of expertise to specialize in. This should be closely linked to the professional field in which you worked before becoming a translator/interpreter, if applicable. For good results, you need to constantly improve your language skills in both the source and the target language. Source language is the language in which the original document to be translated into the target language is drawn up. Usually, translators must be up to date and constantly improve their knowledge of the source language, assuming they live in the country where the target language is spoken. Here are some things that you can do and may prove useful in this endeavor: read all kinds of newspapers or magazines in the source language, but do not ignore the Internet materials; stay up to date with expressions, words borrowed from other languages and used in different dialects or slang; spend as much time as you can in the country where the source language is spoken, having social interactions.
If you have time, start you can begin to study a new language to translate into. Although it may be difficult, this can open up new opportunities and also increase your revenues.
Check the translated text two or three times before delivering the document. A less satisfying result cannot guarantee work continuity, so make sure that you deliver high quality translations. You need to have the best conduct in work and to produce quality results. Do not promise more than you can do, meet the deadlines, respect the client confidentiality and, if applicable, respect your employer.