I was listening to my Mum talking to an Israeli guy who had just started reading the New Testament. He had started with the book of Revelation! My Mum told him, "That's not a good book to start with." "What's wrong with it?" he asked. "Oh, there's nothing wrong with it, but it's just not very easy to understand," explained my Mum.
Some books of the Bible are easier to read than others, so it is important to start reading somewhere that's not too difficult.
If you are new to the Bible and what it teaches, the first few chapters of Genesis would be a good place to start as it tells us how life began and where things went wrong. After that, one of the first four books in the New Testament, (Matthew, Mark, Luke and John) would be good, as they are easy to read and also teach us about Jesus Christ.
If you already know a lot about the Bible, I would probably start with one of the four that I just suggested above (Matthew, Mark, Luke and John).