Sit in a comfortable position and try to be aware of the breath as it enters and leaves the body through the nostrils. You should be able to feel it just below the nose or around the nostrils; this is called the touching point. Touching point is not your meditation object. Your meditation object is breath but you need to feel it on the touching point. Keep the breath natural and do not follow into the body or out of the body. Close your eyes and let everything else go.
Just be aware of the breath as it is, and if the breath is not clear, simply wait for it on the touching point until it becomes clear. Then you will be able to develop your concentration.
Do not pay attention to your thoughts. It is natural loose your concentration and start to think about pop up ideas in the mind. A single thought is a like dust, and can take you somewhere very far from your meditation object. Even may you can not remember how you gone so far and lost in your thoughts. At the beginning success is turning back on your meditation object as fast as you can do. When your mind start to think about something just remind yourself you have to concentrate on your breath. Always be mindful and put effort as much as you need. Too much effort may disturb your mind, cause the mind not to stay calmly concentrated on the breath. Concentration and effort should be in balanced.