Waking up early.
When I was a kid, I never enjoyed waking up early. There was and still is nothing more appealing than your bed when you first wake up and your body is tired. But after working a job that required me to wake up consistently at around the hours of 4 and 5 am, I’ve grown to appreciate the benefits of starting the day before most people and having the discipline to listen to the alarm clock in the morning.
In my experience, starting the day before most has a compounding effect that carries on throughout the day. The action of waking up early puts me into a productive mindset and so any subsequent action that I perform is influenced by that mindset. That is one of the reasons why I think that being productive in the early morning is always easier than being productive late at night.