You should just watch your thoughts like watching a movie. Let one thought come, let it pass, and so on. The moment you hold on to a thought, you start ruminating on it. As most of the thoughts one gets are either of the past or of the future and mostly the thoughts are negative, we tend to put ourselves in a spot. So, just watch the thoughts and let them go. Over a period of time, the gap between thoughts will increase....and that is real silence. That silence will lead you into meditation.