The main obstacle to hear God is our lack of understanding, many believe that we need to be holy and blameless to hear from God. Its true that sin separated man from God, but Jesus came to restore this broken relationship of mankind with God.
God said he will never leave us or forsake us, but we often forsake God, instead of following the spirit we follow the world, and that separates us from God, (but not God from us). When we are saved, only our spirit gets saved, our body and soul are still corrupt, and making them perfect is an ongoing process, also known as growing in Christ. When we sin, we are giving devil a foot hold in our life, and all he does is to steal, kill and destroy.
God always talks to us irrespective of who we are or what we do, in other words our spirit is aways in communication with God. Since we are not living according to our spirit we don't know it or understand it. How many times we come across situations where we knew we were wrong How many times we cried out to ourself “I knew it was wrong”, How did we knew it? Who told us it was wrong? Its God, speaking through our spirit.
God is always talking to us, but we not hearing. For example, most radio stations broadcast 24/7 we wont receive them until we tune in, they don't start broadcasting when we tune in, but we receive them only when we tune in. We sometimes tune into wrong stations, we cant receive CNN when we are tuned in to FOX.
If we don't receive a station its not their fault, it might be our receiver or we were not tuned in. Like wise if we don't hear God, its not his fault, its our fault, we need to tune in to his voice. Jesus said “My Sheep will hear my voice” so all we need to do is some tuning.
Another obstacle of not hearing from God is that many don't know how God talks. He can talk in audible voice or through the word of God or through other men of God, but often he talks to us through that gentle voice in our spirit, our spirit then push them as thoughts into our mind, once we are familiar with his voice, we will hear it loud and clear, knowing him is the key to recognize his voice. Initially we must be very cautious, it can be our own thoughts or the thoughts devil brings in. If we are not sure we need to wait for confirmation, we need to know that all what Gods tells us will be in tune with the written word of God, so we always have refer to it, Its like having a prompter and a map as we drive, if we are are not sure of the prompt we can look at the map, or if we miss a turn in the map the prompter will prompt. Once we start listening to him his voice will become familiar to us, and as it becomes familiar its will be easy to communicate with him.
Next question is how to tune in to God? Reading the word of God and meditating on it, asking God to explain it is what I tried. You will see his words coming to life before you, the verses you read all you life will suddenly become colorful, verses will start popping out at you, yea you wont miss out Gods voice there.
So get ready, raise your spiritual antennas and start tuning in!
God Bless you.