The best way to get better at the craft of translating Japanese is to learn from more experienced translators. There are three ways to do this: in person, in books, and online.
The best way to meet other translators in person is through professional organizations like the American Translators Association (ATA) and the Japan Association of Translators (JAT). When you join JAT you also gain unlimited access to its extensive video archive, where you can watch master translators explain their craft step-by-step. This is a priceless resource and one of the best reasons to join JAT.
With respect to books on Japanese translation, an excellent choice is The Routledge Course in Japanese Translation by Yoko Hasegawa, based on her course on Japanese translation at UC Berkeley. Also excellent is the Technical Japanese series published by the University of Wisconsin Press.
Finally, there are plenty of places online to find high-quality business translations that you can use as a model. Large Japanese companies publish press releases, annual reports, and technical manuals in both Japanese and English on their websites. If you are handy with a CAT tool, you could even use its alignment function to make translation memories from these bilingual documents for use in future translations.