Gratefulness is an energy, and an attitude, and a style or pattern, and a spirit. It can be thought of or described many ways. Everyone though, will probably agree that it is a good feeling. It is positive. This positive emotion is the foundation for being open to positive change, positive receiving, and positive discovery.
It is its own reward. To be in this feeling before good things come or in the face of obstacles gives one a strength and inspiration that brings wonderful things to your life and prepares you for the actions needed to pass through a challenge.

A good practice is to be aware of when your mind is feeding on negativity, criticism, judgement, or victimhood. In that moment, you can make a choice of what your next thought will be. You will be gratified if you find a positive thought or one of gratitude. You do have control over your thoughts. A favorite saying of mine is "You don't have to believe everything you think" Just because a negative thought is in your mind doesn't make it true.

See if you can make a habit of noticing negative thoughts, particularly chronic ones and switching to something to be grateful for. Immediately, the energy in your body and mind will switch. You will be nourished by an infusion of positive feeling and remembrance. You will even begin to change the hormonal functioning in your system. Think of the difference of the state of your mind and body when you feel anger, fear, anxiety and when you feel love, joy and freedom. These are actual differences in your biochemical/energetic state.

Isn't this a good reason to make a simple decision to switch to gratitude and to make it a habit?

Make it a game or make it a discipline. Just start noticing and switching. It's a habit worth cultivating.
http://www.personal-growth-and-freedom.com/gratitude.html

Author's Bio: 

In my life, there are two main themes that are parallel and intertwined. In broad strokes, they could be described as spiritual and material. In my early twenties, I had a profound spiritual experience that changed my life forever. During the time of this transformation, I went to India, spent time with Maharishi Mahesh Yogi and became an instructor of transcendental meditation.
Here is a scene from the ashram I was at. In the center are Maharishi Mahesh Yogi and a visiting Indian saint, Tat Wale Baba.

When I returned to the states I initiated hundreds of people into meditation and began a lifelong journey to fulfill myself spiritually.

Also, like most people, I had to learn how to earn a living and achieve material success.

After completing graduate work in counseling psychology, I became the head counselor in a program for poverty level school dropouts. Later, when I married, and had my first child, I became dedicated to a career in business. I created and ran companies at both the retail and wholesale levels, with and without partners. I also served as a national marketing director for a manufacturing company.

Twice, I built companies to among the largest in the nation in their niche. Following that, I have worked as a small business advisor specializing in marketing and exit planning.

All during that time, I practiced meditation daily, led groups and taught individuals various spiritual practices. I also studied, practiced, and taught various “release” techniques. In the mid 90s, I graduated from CoachU to add those practical skills. I think it is very important to have a daily practice that gives us the tools to have a full, rich, balanced life in all areas. I find that many people have adapted to the challenging, achievement oriented lifestyle of our postindustrial, information-based society. Yet, many are still searching for deeper peace and resolution of conflict.
http://www.personal-growth-and-freedom.com/About-Jim-Gillette.html