This is a very important question and one worth spending some time on.
The first thing to note is that God does speak to us. Its quite an amazing thing to think that the creator of the universe wants to speak to you and me. But that is the reality of it!! He is not a God who hides so that we have to search for him and coax him out, nor is he a God who has nothing to say! Rather he is a God who wants to speak to us and has made the effort to speak to us. Indeed he created us in order to have that sort of relationship.
Now if God has done this then our responsibility is to listen. And this is the heart of your question - how do we hear God’s voice?
The first thing to note is that God can speak to us in whatever way he likes. He is a powerful and sovereign God and can speak to us by a voice we hear, by dreams, by visions and even writing that magically appears on the wall!!
However, the Bible teaches us that God promises to speak through the bible (2 Timothy 3:16). The Scriptures are described as “breathed out” or inspired by God and as the Word of God are all that we need to know about how to live. God’s ultimate “speech” to us was his Son Jesus who is “the Word of God” and as such comes and tells us what God has to say.
This is very important for it means that while God can speak to us however he likes, he has promised to speak to all of us through the bible. So if you want to hear God, read, study and discuss the bible with others, always asking God before hand to speak to you in what you read. This helps us in two important ways:
Firstly, anything we think or believe about God must be measured against the Bible. If what we think God is saying to us goes against what the bible says, then it is not God talking to us. This is how we recognise Satan’s voice - it will not be in line with the Bible.
Secondly, it means that we won’t waste time searching for God’s voice outside the Bible. If you want to hear your favourite band you check the tour dates and you go to the correct venue on the correct night. You don’t say - well they might play at this particular club tonight so I will go there. No, you go by the published tour dates. It is similar with God - he has promised to speak to us in the Bible and he has told us that the Bible is ‘living and active’ (Hebrews 4:12) - it is not a boring old document - it’s God’s living and active word.
So, the answer to your question is that I know that God is speaking to me when I read the Bible. So the most important thing you can do when you read the bible is to ask God to speak to you through it.
I hope that helps - please come back to me if you have other questions.
For more information have a look at: