One big prerequisite is that you should be lucky enough to have a smart brain. The smarter the better, of course, for the simple reason that you bathe either in dopamine or in norepinephrine (analogous to heaven and hell, I dare say) depending on whether or not you can learn anything and everything instantly and instantaneously from the Internet Guru and express it in the target language at least better than the author did in the source language.
A translator who can rapidly and efficiently acquire ad hoc knowledge–in the sense that that knowledge is acquired and used for the exclusive purpose of translating the manuscript at hand–and convey complicated information concisely and clearly is like a lion in a jungle. Better still: such translators need not go hunting; they are spoon-fed by their agencies. Not only do they earn money and learn things while having fun, they also contribute to the global community by adding one more gem to the ocean of collective intelligence everytime they finish translating a good piece of academic work (I mean, better than anyone else would have done).
To the truest sense of the word, I am a happy inhabitant of a paradise and count my blessings every day. Thank you world, and thanks to the Internet that makes my life worth living for myself and for others.