When it comes to listening for the voice of God, I think I have to say that I don't have much to say. About the only thing I think I can say with some confidence is that I'm not much of an expert on the topic...that I don't do it well.
What does God's voice sound like? This is a question that I have asked a lot of people. My answer has always been that it sounds like the voice in your head, it sounds like your voice. This has to be true or else it would be a whole lot easier to know whether or not I had heard God's voice. I would only have to evaluate the strange sounding voice to determine it's validity.
When I am preparing a sermon I am pretty sure that some of the great insights that come along are the voice of God. I have listened to portions of a sermon or have had people come up to tell me something that impacted them from the sermon and upon reflection, it could only be attributed to something God had said/done. I often say to myself 'I couldn't have come up with that on my own'.
In talking with a 'worker' recently, I asked the same question 'how do you know what God's voice sounds like...that it is Him speaking?' and she told me, "it sounds like my voice but with a twist".
I think I like that. When I'm listening for God's voice it is going to sound like mine, but with a twist. With that certain 'I wouldn't have necessarily come up with that' sense to it. I suppose I have to leave room open for the possibility that I could have come up with it, but all the same it is going to sound kinda sorta like my voice. At least that is the starting point.