Psychologists agree that, if you want to be happier in life, it helps to cultivate a feeling of gratitude. For example, see this video regarding Sony Lyubormirsky's research into the impact on happiness of writing in gratitude journals: Lyubormirsky on You Tube. One of the surprising things about this research is that writing down what you are grateful for has a much bigger impact on happiness for most people if you only do it once per week versus the group that did it 3 times per week or the control group that didn't do it at all. Why? The professor concludes that if you do it too often, it becomes a chore. You don't feel energized.
Imagine if there was another way to cultivate gratitude, a method that you could use every day and always feel deep emotional appreciation for the blessings you are counting. How to do this? One option is to apply the methods of the ancient Stoics--the Greek and Roman philosophers whose philosophy thrived between 350 BC and 200 AD (Stoicism-Wikipedia). I recently read "A Guide to the Good Life (the Ancient Art of Stoic Joy)", by William Irvine. The author is a professor at Wright State University who is convinced that many of the practices of the Stoics can be applied to modern life. He feels that the common view of Stoics as serious and unemotional is wrong and that they actually had practical advice on how to cultivate deep appreciation every day for what you have. In other words, the Stoics developed methods to cultivate a gratitude attitude.
Their key method for this is now described as "negative visualization". Here is a link describing it: negative visualization. The idea is to recognize that you never know when you could lose something around you that you cherish. There are no guarantees that your dog will be here tomorrow, or your house, or your family, or your job, or the nice weather outside, or your health, or your life. The idea isn't to dwell on these thoughts morbidly, just to quickly acknowledge the fact that these things are not necessarily permanent. This sounds depressing, but the result--according to the Stoics--is great joy. A few minutes a day of this practice, applied to a few things around you, can cause you to take nothing for granted. You cherish what could perish, and when you recognize the reality of change and impermanence, you are more likely to care deeply about what you already have.