What is unknown ?
What data is available ?
What is the condition ?
Can condition be satisfied ?
Is condition sufficient ?
Is condition redundant ?
Is condition contradictory ?
Can you draw a diagram ?
Can you device some notation ?
Have you seen problem before ?
Have you seen problem in similar form ?
Could any theory/theorem/tools be used ?
Could you restate the problem ?
Could you review the definitions ?
Can problem be decomposed into smaller problems ?
Is there a more general problem ?
Is there a more specialized problem ?
Could you solve a part of the problem ?
Could you relax the condition ?
Could something useful be derived fr the data ?
Did you use all the data ?
Did you use all the condition ?
What are the assumptions ?
Can assumptions be challenged ?