How to Apply Kantian Ethics

I have read extensively on both John Stuart Mill's Utilitarianism and Immanuel Kant's Ethical Theories, and yet, my feeling is that Kant's writings are both an order of magnitude more extensive and more complex than Mill's, leaving me feeling confident only in putting Mill's Utilitarianism into practice via thought experiment.

Q: Can anyone offer me a step-by-step example of working through an ethical question, dilemma, situation, etc. via Kantian Ethics?

I'll leave the precise situation up to you but please chose something different than any of the examples Kant offers in Part II of the Groundwork for the Metaphysics of Morals. Many thanks.