The spiritual exercise of offering gratitude to God is as old as the ancient stories found in the Hebrew Bible. The first record of showing gratitude toward God in the Old Testament is found in I Chronicles, which was written around 450 B.C.E.
Give thanks to the Lord and proclaim his greatness. Let the whole world know what he has done. Sing to him; yes, sing his praises. Tell everyone about his wonderful deeds. Exult in his holy name; rejoice, you who worship the Lord. Search for the Lord and for his strength; continually seek him. Remember the wonders he has performed, his miracles, and the rulings he has given, you children of his servant Israel, you descendants of Jacob, his chosen ones.
I Chronicles 16:8-13
Take time every day to say "thank you" to God. A good starting point is to thank God for the gift of life itself. Being thankful for all the good things - big or small - can help you to see other things with new eyes. The more you practice this exercise the more aware you will become of God's everyday gracious presence.
Take your time and don't rush as you think back over your day to find things to be grateful for. If you find something specific every day to thank God for, you will begin to change your whole perspective on life.