How can I debug a failing `setup.py` script?

Add `print()` statements within the `setup.py` script to inspect variable values and execution flow. You can also run the script directly with `python setup.py` (without `install`) to see if it executes without errors. Use a debugger (like `pdb`) to step through the code and identify the exact line causing the problem. Check for typos and incorrect assumptions in the script.