How to accomplish an Anonymous Email login? Which info are tracked by servers when you log in?

Hi guys!

I just wrote a simple script in python that is able to enter my email account. What I wanted to know is: what should I consider in order to cover any information when logging in my mail account?

With a proxy I can cover the IP, but which other information are tracked by the server? and how to hide them in order to be completely anonymous?

Thank you