[Paul-Craft]

The inverse of this strategy also works well sometimes: try to solve a more general (i.e. "harder") version of the problem. Examples:

* https://math.stackexchange.com/questions/899109/problems-tha...

* https://mathoverflow.net/questions/21214/particular-problem-...

The second link has the neat particular example of showing that something is nonzero by showing that it is odd, which I quite like.

[lqr]

Agreed!