Important things to keep in mind when reading the Bible:

First

You must always consider its context. In order to understand any writing (whether it be a letter, a speech, or even the Bible) it is necessary to understand its background. Think about who is speaking, to whom it is addressed, why it is written, and what the culture was like.

In the case of Scripture, the cultural and social context of biblical times was very different from our own. For example, when the Bible says God commands humanity to "increase and multiply", remember, among other things, this was addressed to Israel, a small, desert nation surrounded by many enemies. They needed to "multiply" just to survive.

Second

The Bible began as an oral tradition and then was written in ancient languages (primarily Hebrew in the Old Testament and Greek in the New Testament) over many centuries. It was copied nd re-copied in the original languages. As anyone who speaks or reads more than one language will understand, translating requires interpretation and personal judgement. Even with the best of intentions, translators and copyists are quite capable of human error.