Requests login failure

[test]

Sir, it would be extremely helpful (not just for me, i think) if you could post your general thought process in figuring out what exactly has to be passed.
Thank you very much

For example, the following code just does not work again...

#wreqt.py

import requests
from bs4 import BeautifulSoup
from lxml import html

headers = {'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36'}


params = {	'acountName'	: '*****',
			'password'		: '*****',
			'useSrp'		: 'false',
			'publicA'		: '',
			'clientEvidenceM1'	:	""	}
					
					
with requests.Session() as session:
	session.post('https://us.battle.net/login/en/', headers = headers, params = params)
	response = session.get('https://us.battle.net/account/management/')
	tree = html.fromstring(response.content)
	balance = tree.xpath('//*[@id="primary-balance"]')
	print(balance)

Running this code outputs an empty list, while it should be the available balance for a user. As I am trying to learn the implementation for requests in general, and not just a specific case, can someone please explain how i can figure out what has to be passed to make it work everytime?