make sure you use tabs to format all of your Python code
I disagree. Idiomatic Python uses 4 spaces per indent.
Either solely use tabs or solely use spaces, they don’t work well together, at least in my experience
Mixing tabs and spaces is indeed very unwise. You can run Python with the -tt option to make sure you're consistent.
Read Style Guide for Python Code for more advice on this front
I agree ;-) The author probably refers to PEP8, http://www.python.org/dev/peps/pep-0008/