The Hebrew word for gratitude is hikarat hatov. Hikarat hatov literally means "recognizing the good." When we look around at our circumstances and our blessings and seek reason to express our gratitude, then we are truly exemplifying the middah of gratitude.
If we look upon our blessings and regard them as things we expect to have, we are missing out on gratitude. Nothing is guaranteed in this life. Everything we have is a gift, and we should respond in kind.
Sensitize yourself to the blessings around you and practice this simple meditation daily:
You are alive today. This, in and of itself, is a gift. Breathe deeply in and out and regulate this breathing. Deep breathing brings oxygen to your brain and helps clear the mind. This is also a gift to your body.
Focus on the verse:
Hodu L'Adonai Ki Tov, Ki L'Olam Chasdo.
הוֹדוּ לַיהוָה כִּי-טוֹב: כִּי לְעוֹלָם חַסְדּוֹ
Give thanks to Hashem for he is good and his mercy endures forever.
Concentrate on this verse. Consider all your blessings, from rising in the morning to eating, breathing, walking, drinking, etc...There is nothing you have today that did not arise from the chesed of Hashem. As you keep repeating this verse, keep counting your blessings and calling to mind all of the bounty that you have. Do not think about what you don't have; rather, focus on all that has been given to you.
This exercise will help you achieve mental focus, awareness of your behavior, and a moment to illustrate your necessary work with regard to gratitude. If you are easily able to recall your blessings and come before Hashem in gratitude, you can better participate in your daily walk knowing how much you have to offer and how fortunate you are.