[mmccomb]

Hard work alone is often not sufficient. The real solution is to work hard but also to work smart. You need to find a balance between slogging just to get things done and innovating to reduce the slog required in the future. This applies not apply to physical tasks but also to learning. When learning a new skill/subject it's easy to expend a lot of effort reading whole books and articles without taking the leap of getting your hands dirty and applying your learning, but without doing so you can't build the neural connections required to learn.

[SergeyHack]

Also I would say "hard work" is a bad metaphor. More important parts are:

1) (as you said) "work smart"

2) "enjoy your work"

and only then 3) "work hard"