Breath is the easiest way to detach from our thoughts. As you begin this or any other breathing exercise, remember that it is normal for the thoughts to distract you or take over your concentration. When this happens there is no need to panic or get annoyed with yourself. Simply recognise that your concentration has diverted, take note of anything useful that may be appearing in your mind field and come back to the exercise you started. It is helpful to keep a journal next to you to note down any useful experiences during the practise. Its alright to pause, write down and then go back to the exercise.