If you are having trouble thinking of something to be grateful for, Oprah says that when all else fails, close your eyes and breathe. Just breathe, and you will be reminded that you are alive. Consciously recognize that your lungs are filling with oxygen that are pumping blood to your heart causing you to be here in this beautiful moment.
If you want to take it a step further, physically list 5 things you are grateful for each day. They can be "simple" amenities such as electricity. We don't realize it, but electricity is a phenomenon. There is energy being transferred from an electrical source traveling at rapid speeds to provide light for our homes, offices, stores, etc. Think of how lost you feel when the electricity goes out during a thunderstorm. From that, you can be grateful for something like your TV. Your TV provides you with breaking news and instant entertainment all with the click of a button, literally!