Working from home: winners, losers, and making lemonade

At some point between March and April, two-thirds of humanity was under lockdown due to the Covid-19 pandemic, and a significant portion was working, or struggling to work from home.
What does this entail? What are its unique opportunities and challenges? Which coping strategies function best? And what does this portend for the future, or at least until specifics and a vaccine are discovered?