Key steps in programming

Which of the following would you consider key steps when solving a problem with programming?

Getting all program output in correct format.
Writing algorithms that solve the subproblems.
Understanding the problem.
Testing the solutions for the subproblems.
Dividing the problem(s) into subproblems until you find problems that can be solved independent of the others.
Implementing algorithms using a programming language.
Trying to write some sort of solution all at once to get something working.