How to use meditation effectively & practically

You do not need to become a barrier to worldly thoughts, but let them come and let them go. And in the process become aware of your state of mind and thereby only allow positive and peaceful thoughts to flow into the mind. As the skill sets in, you would adept at centering on deep breathing effortlessly. And in some time you become virtually aware of each and every breath that comes into your system and the breathing flow out.