First: how are you currently being grateful? The likelihood that you are already on the gratitude path is quite high.
Gratitude consists of living fully, without recklessness, loving others who seem unworthy of love, forgiving yourself, keeping hope alive, identifying what makes you happy and living it, identifying what makes you unhappy and categorizing it into: manageable, requires skills acquisition, requires others' help. Living everyminute.
Make a list o 25 things you want to do, acquire and/or feel before you die.
Make a list o what scares you. and be generous.
"IF" by Rudyard Kipling may inspire you. Also: "Veronica decides to die" by Paulo Coelho