Principles are ways of successfully dealing with reality to get what you want out of life.
Ray Dalio, one of the world’s most successful investors and entrepreneurs, cites principles as his key to success.
Ideally, someone other than you should be objectively measuring and reporting on your progress. If you're not hitting your targets, that's another problem that needs to be diagnosed and solved. There are many successful, creative people who aren't good at execution. They succeed because they forge symbiotic relationships with highly reliable task-doers.
That's all there is to it!
Remember that all 5 Steps proceed from your values. Your values determine what you want, i.e., your goals. Also keep in mind that the 5 Steps are iterative. When you complete one step, you will have acquired information that will most likely lead you to modify the other steps. When you've completed all five, you'll start again with a new goal. If the process is working, your goals will change more slowly than your designs, which will change more slowly than your tasks.
One last important point: You will need to synthesize and shape well. The first three steps--setting goals, identifying problems, and then diagnosing them--are synthesizing (by which I mean knowing where you want to go and what's really going on). Designing solutions and making sure that the designs are implemented are shaping.