DON'T STOP WITH ONE IDEA: The more ideas you have, the better your chances of finding a good one. Don't be afraid to keep asking questions. Look for alternatives. Never just settle for one answer.
My teams have learned to continue looking for more solutions, even after they think they've solved a problem. They've learned that often their best idea comes later in the game. But, if they do forget to keep looking for ideas, I'll ask them, "What's another way you could do it?" Just the reminder to keep at it helps them to work until they reach the best possible solution.