Whenever you encounter a brief, precious moment (such as when you are with your loved ones, when you are in some new place overseas, etc), pay close attention to it with your senses for a while and then close your eyes.
With your eyes closed, imagine yourself on an ordinary day in the future, in your bedroom at home, scanning its surroundings as you’re lying down on your bed. Look at the ceiling, the desk, the bed, the fan, the window, etc. In a way, you’re forcing yourself to "dream" that you’re at home for a while.
Then, open your eyes to be aware that this precious moment in the present is “reality”, and you being in your bedroom was actually a "dream".
Realise that in the future, the reverse will be true. You’ll be savouring this precious moment in the present in your “dream” while asleep, and when you open your eyes, you’ll realise that your “reality” is you being in your bedroom.
It’s easy to get lost in the mundane day-to-day life, going through the motions, and miss out on treasuring what we have in the present. Our loved ones will not be around forever. Amazing moments in our lives are over in the blink of an eye. Our bodies will not feel the same way as we grow old. We’ll never know when is the last time we’ll get to be with someone, go somewhere, or do something.
This exercise helps bring awareness to the preciousness of life’s moments, and can induce a sense of gratitude when you appreciate the fleeting nature of the “now”.