It has to do with not trying to block out the world around you, but to get still and be with it. Open up to the senses and observe your mind's movements. Does this sound or that one irritate you? Why?
Meditation is about being attentive to one's thoughts and eventually seeing through the folly and delusion of those thoughts. Don't TRY too hard to get rid of thoughts. It is a natural function of the brain. Sit still, watch your breath, give yourself a little time and your mind will NATURALLY settle. Practice.