Start again with better questions.

A restart with the original questions tends to produce the original answers. What actually changes the second attempt is asking something different: not how to make this work but whether the framing was right, not how to try harder but what you were wrong about. Better questions do more than better effort.

Before you begin again, write the questions you were implicitly asking last time and try to improve them. Notice how the plan changes when the question does. This is usually where the real revision happens.