The following are some quotes that just might inspire you to bring more gratitude into your life:

“As we express our gratitude, we must never forget that the highest appreciation is not to utter words, but to live by them.”  
~John F. Kennedy

“Saying thank you is more than good manners. It is good spirituality.”  ~Alfred Painter

“At times our own light goes out and is rekindled by a spark from another person. Each of us has cause to think with deep gratitude of those who have lighted the flame within us.” 
~Albert Schweitzer

“The deepest craving of human nature is the need to be appreciated.”  ~William James

“Let us rise up and be thankful, for if we didn't learn a lot today, at least we learned a little, and if we didn't learn a little, at least we didn't get sick, and if we got sick, at least we didn't die; so, let us all be thankful.”  ~Buddha

“I awoke this morning with devout thanksgiving for my friends, the old and the new.”
 ~Ralph Waldo Emerson

“Gratitude is the fairest blossom which springs from the soul.” 
~Henry Ward Beecher

“Appreciation can make a day, even change a life. Your willingness to put it into words is all that is necessary.”  
~Margaret Cousins

“Gratitude unlocks the fullness of life. It turns what we have into enough, and more. It turns denial into acceptance, chaos into order, confusion into clarity.... It turns problems into gifts, failures into success, the unexpected into perfect timing, and mistakes into important events. Gratitude makes sense of our past, brings peace for today and creates a vision for tomorrow.” 
~Melodie Beattie