One of the best practices is, to define a common style guideline. So that it would be much easier to understand a codebase when all the code in it, is in a consistent style. Specially if you are working in a team. PEP (Python Enhancement Proposals) provides a good starting point to define those style guide.
Here are some highlights which are mostly from PEP 8, but also from other best practices:
Avoid one letter variables like x and y (Except in very short code blocks). Give your variables and functions a meaningful name and use follow naming convention:
Variables, functions, packages and modules names should be:
Classes and Exceptions