""23 things I didn't learn in college / grad school":

#5: Show up

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Really restating Somerset Maugham's famous line: “I write only when inspiration strikes. Fortunately it strikes every morning at nine o'clock sharp.”

The easiest way to lose steam on any effort -- writing a book, taking a Coursera class, training for a marathon, setting up a weekly collaboration -- is not to show up.  Maybe it's daunting or you haven't done your homework, but not showing up only makes it worse, not better.

If running 5 miles on a cold morning feels too hard one day, walk 3 miles.  If you didn't do your homework to prepare for a meeting with a colleague, still show up and tell them you are unprepared, and use the time wisely perhaps to recap the state of the discussion.

New year resolutions around gym and exercise are famous examples of people not showing up for what they signed up for (see https://www.bloomberg.com/news/articles/2019-01-16/here-s-how-quickly-people-ditch-weight-loss-resolutions).  But if you're constantly "flaking", it's a sign you're over-committed.   Be honest with yourself and reduce your commitments.

Anybody can sign up for things.  Showing up is the really important part.  Good luck!