At the end of the day, you find some quiet time with yourself so you can reflect. Recall and relive the day in your mind, from morning until evening—what did you do, what happened in your day? If you had a bad day, let it go and focus instead on the good things that day. This is a habit and actually a skill that will take some time to practice in order for it to develop so hang in there and just keep at it every day. Good luck!
I tend to look for the smaller things that can easily go unnoticed otherwise and I don’t worry if it’s something new or not, only if it happened that day.
The only change this has to my day is now I’m a little more in tune with noticing things to be grateful for as they happen as opposed to getting to the end of the day and finding it hard to think of the things to be grateful for.