Terence Tao quotes

Understand the problem. What kind of problem is it? There are three main types of problems:
‘Show that ...' or ‘Evaluate ...' questions, in which a certain statement has to be proved true, or a certain expression has to be worked out;
‘Find a...' or ‘Find all...' questions, which requires one to find something (or everything) that satisfies certain requirements;
‘Is there a ...' questions, which either require you to prove a statement or provide a counterexample. (Terence Tao)

Relying on intelligence alone to pull things off at the last minute may work for a while, but generally speaking at the graduate level or higher it doesn't. One needs to do a serious amount of reading and writing, and not just thinking, in order to get anywhere serious in mathematics.

Terence Tao