>>82430530 (OP)
you literally stop them. i started practicing this when i used to really struggle to sleep due to endless thoughts whirring around. basically whenever you think something, consciously eliminate it from your mind, stop it mid sentence as it were, so there is just silence, at least for a moment. it can be difficult, but once i've managed to stop the first thought each night, it becomes easy and sleep is nearly immediate. i guess it could work throughout the day also