Meditation
There are certain habits that seem so beneficial at such low cost they are incredibly easy to make. A basic litmus for this is how often do people regret doing it.
I’ve spoken to and met a lot of people who meditate and I’d say about 0.1% regret it which means if you meditate you’re (about) 1000x more likely to be happy you did than regret it - lets looks at statistics 8% of people report an adverse event, i.e at least one negative event - you’re 12x more likely to not have a single negative event than you are to have at least one negative event and those single negative events are usually transitory; the cost of meditation is very low (anywhere from 5-20 minutes per day has benefits with most benefits taking 20 minutes per day, that means for the cost of (at most) 20 minutes per day you sleep better, think clearer, have higher stress resilience, recover better, improve anxiety and depression, improve pain tolerance, improve memory and your immune system - there are additional benefits these are just ones with significant effect sizes.
In terms of the practical, I meditate (anapanasati) for 10 minutes in the morning then do 10 minutes in the evening with whichever type of meditation will give me what i need at that time. The reasoning is attention is very important to me and anapanasati has the most research behind it at improving attention (depth and span) however before sleep in some people it can increase agitation and decrease sleep quality, if I think for a few minutes I can usually figure out what change to my mental state is most needed to improve my sleep then I apply the appropriate type of meditation - as a buddhist I stick firmly to buddhist (religious) forms of meditation so sometimes it’s recitation and forms like that but this approach can be adapted for most people.