اللَّهُمَّ مَا أَصْبَحَ بِي مِنْ نِعْمَةٍ أَوْ بِأَحَدٍ مِنْ خَلْقِكَ فَمِنْكَ وَحْدَكَ لَا شَرِيكَ لَكَ، فَلَكَ الْحَمْدُ وَلَكَ الشُّكْرُ
Allahumma ma asbaha bi min ni'matin aw bi ahadin min khalqika faminka wahdaka la sharika lak, falakal-hamdu wa lakash-shukr
O Allah, whatever blessing I or any of Your creation has received this morning is from You alone, with no partner. So for You is all praise and to You is all gratitude.
Recite every morning (change 'asbaha' to 'amsa' for evening)
The Prophet (PBUH) said: 'Whoever says this in the morning has fulfilled the gratitude of that day, and whoever says it in the evening has fulfilled the gratitude of that night.'