It is customary to pray before a meal. While in church. When you wake for the day. And when you go to sleep at night. What is not so customary is to randomly chose a time a place out of the norm. Just simply have a conversation with God. In fact try not to include I in the conversation. Try being humble. Let what ever you feel be expressed. Many may say, "How do I know God hears me?" He hears you. You have to trust and believe. There is no one walking this earth today who is an expert on God. So the focus cannot be from a mans point of view it is who and what God is to you that is important.