Whilst many translators have at least a Bachelor’s degree in either translation, languages or a field related to their specialism, there are some excellent translators out there who do not. The same goes for the various diplomas, additional degrees and memberships, to some extent. Whilst
these are an indicator of talent, the ultimate test is satisfied repeat clients, who also pay the translator concerned a fair wage. This is not to say these qualifications and memberships are by any means worthless, just that, by themselves, they are no guarantor of success, nor is one without them doomed to failure.
In addition to the pure linguistic skills, you should also be familiar with how the language is currently used, together with commonly used slang, dialect, and new words borrowed from other languages (if appropriate).