You should not put too much trust in any unproved conjecture, even if it has been propounded by a great authority, even if it has been propounded by yourself. You should try to prove it or disprove it.

Success in solving the problem depends on choosing the right aspect, on attacking the fortress from its accessible side.

If you have to prove a theorem, do not rush. First of all, understand fully what the theorem says, try to see clearly what it means. Then check the theorem; it could be false. Examine the consequences, verify as many particular instances as are needed to convince yourself of the truth. When you have satisfied yourself that the theorem is true, you can start proving it.

If you cannot solve the proposed problem try to solve first some related problem.

My method to overcome a difficulty is to go round it.

There are many questions which fools can ask that wise men cannot answer.

John von Neumann was the only student I was ever afraid of.