All translation is interpretation of some sort; What is a good practical method(s) for seeing through the bias of translators and teachers to arrive at the best understanding of the original meaning and presumably lead toward truth?
The philosophy of interpretation is called Hermeneutics, and the canonical text in the field is Gadamer's Truth and Method.
Note that this applies also when reading in your native tongue; every act of reading is also an act of interpretation and translation.
Unfortunately, the only answer here is to learn the language and translate it yourself. You might go some of the way towards eliminating inaccuracies in translations by comparing a number of different translations.
As for eliminating the bias of teachers, this tends to be something you get better at the more you learn. When you become an expert in a subject matter, by, say, reading more of the primary texts, you will naturally begin to disagree with your teacher on various points of interpretation. Similarly, if you read the teachings of multiple people with divergent views you might be able to isolate the idiosyncrasies of each approach.
So, to sum up, it seems the best "method" is to not wed yourself to one particular translator/teacher and to compare what you're exposed to in order to isolate common themes and note idiosyncrasies.