[alibero]

I feel like this is a boring answer but for me, I had to make a habit of it, and then it didn't feel so hard any more. I started doing a master's degree in my free time: when I started I barely had the energy to do anything outside of work, but now I feel like setting aside time for coursework is pretty natural.

For me I find I usually fall into a 2/2/2 pattern for forming habits*: The first two days are super hard, after about two weeks it starts to feel doable, after two months the habit is pretty set and I don't have to worry as much about falling off the bus.

* This entire pattern is probably a placebo but that's fine by me

Of course, your energy is not infinite. If you are trying to work crazy hours and fit in other taxing activities, you are going to fail at some point.