Using a light theme, when working at day and a dark theme, when working at night works best for me, I found.

macOS can switch it‘s theme automatically, depending on the time of the day.

Some editors, like TextMate, support automatically changing their theme accordingly.

If you use it: George Nachman, creator of iTerm, announced it will also be able to switch its theme in that manner.

I'm sure other shells and editors support this feature too or will be.