In my experience, God has spoken to me when I have really laid everything aside to seek Him in prayer. Its like when I'm praying, He will interrupt me, usually with a word of correction like "what you said this morning was wrong" or with a word of encouragement like "be strong". He also speaks to me through circumstances or other people, it's like someone or something will confirm something or answer a question that I had been asking God. But in all things, I try to be sure that it corresponds to the Bible, otherwise it cannot be God.