I found mental Silence to be very powerful. Actively shutting down any thoughts, because it is here that we experience Peace, if only for a moment. Our thoughts draw power from being thought ( (sounds funny, doesn't it ;))
But the more we think a thought the heavier it gets and exhaust us. We need to unplug it. Thinking is an act of Separation, the source of all worry and doubt. By exercising mental silence we reconnect with our Heart, and hence gradually start having more peaceful and harmonious thoughts again.
Our mind is quite chattery, so it might take a bit, but the more we practise it, the better the results. I hope this helps! :)