This is how you become the best you can be, which will undoubtably bring happiness.
For example: Something you're passionate about is life. So become immensely interested in it, and continue to let that interest grow. Look around you and see the beauty of the world. Keep your head up and see the people around you. Lift them, and allow them to lift you. Foster life-long relationships with others, and don't let petty things keep you from holding fast to those friendships. Call your family members, both close and estranged, and ask them how they are doing. Learn about other cultures and develop a respect for them. Eat good food and go on long walks. Find yourself in the mountains with good people and a good view. Read books, and then read some more books, so that you can have more insight to things around you. Look down from the tops of man-made skyscrapers God's peaks and canyons. Admire the beautiful artwork and architecture around us, and immerse yourself with beautiful melodies and music that move the soul.
These are just a few ways to show that you appreciate this life you've been given. Be grateful.
And doing this doesn't ensure that there will be no bad days or hard times, but it does make those times less bad and less hard. It gives you things to be grateful for even in moments of distress and sorrow.
