Practicing gratitude is probably the single easiest way to increase one's happiness, and yet it's so easy to forget to do it even if you know that. At least for me.
One thing we can do is keep a gratitude journal where we write down things we're grateful for. Can literally be grateful for the sun shining, or not experiencing an earthquake, for having the ability to write in a journal in the first place, etc.
No woo woo necessary. You may be interested in checking this (and related citations) about research on gratitude and psychological well being:
https://en.wikipedia.org/wiki/Gratitude#Psychological_interv...