I know, books have been written on this topic. But here are three rules of thumb that will set you on the right track:
(1) Don’t choose one. Choose many. Compare translations. Do you prefer ESV or (T)NIV? Okay then, compare it with NRSV and REB. Compare the translation you use with a paraphrase like the Message. It will get you thinking and noticing things you would otherwise miss. If you wish to understand the Old Testament, get a copy of the Jewish Study Bible, which gives you the New Jewish Publication Society Version. You will be happy you did. Comparing translations will bring aspects of the text to your attention that would otherwise escape you.
(2) Find a translation that is based on another translation. That may sound like strange advice, but it is important to see clearly that translation is also interpretation. If you read a translation of a translation, you will discover, by means of contrast, how you slant the biblical text according to the cultural and theological coordinates you take for granted. English translations of the Septuagint, the Vulgate, the Targums, and the Peshitta are not as widely known or as readily available as they should be. In a future post, I will link to details on English translations of the ancient versions.
(3) Do you know a foreign language? Even if your Spanish, French, or German is lousy, you will learn a lot if you read familiar passages of the Bible in a foreign language. All of a sudden, you will see things and hear things you missed in your mother tongue.