I first appreciate the blessing given to me that my conciousness was able to notice the thought in the first place. Then, I begin searching as to why I might have that thought, usually the answer is always "fear". Then, I try to find something good about having that thought (i.e. I was able to notice it, appreciate it, and realize it for what it was...unfounded) I do not judge myself for having the thought. Then I move my attention to something I am enjoying at this very moment...which is usually nature, a scent, a sound, or a sensation. Its worked miracles for me. And there are always deep breaths in between these thoughts...to stay present.