Python programming - Kaizen way

When programming with Python, I always feel that I have 3 stages.

Stage 1 - python as a script

In this stage, I normally don't know what I don't know. So, I just use python's method to get the functionality I need. Python is superb: it has almost every library I need, it has every container I need, and it means I can code pretty fast.

Stage 2 - python as a procedural language

When I pass the stage one, I can see the methods(functions) that I need to make as I see the duplications clearly. with def, I extract duplicate code into a method.

Stage 3 - python as an OOP language

In this stage, I can see what module/class I need to make. I extract methods into a python class, and I can easily separate the client and python object.

Things to consider

With this three stage python programming model, I need to answer those questions.

1. What refactoring tools do I need to get the kaizen work effectively?
2. When do I need to start making testing code?
3. What method/technique do I need to be more effective? logging the procedure?