This thread seems to be quite old. If anyone's still looking, the steps mentioned here : https://github.com/burnash/gspread work very well.
import gspread
from oauth2client.service_account import ServiceAccountCredentials
import os
os.chdir(r'your_path')
scope = ['https://spreadsheets.google.com/feeds',
'https://www.googleapis.com/auth/drive']
creds = ServiceAccountCredentials.from_json_keyfile_name('client_secret.json', scope)
gc = gspread.authorize(creds)
wks = gc.open("Trial_Sheet").sheet1
wks.update_acell('H3', "I'm here!")
Make sure to drop your credentials json file in your current directory. Rename it as client_secret.json.
You might run into errors if you don't enable Google Sheet API with your current credentials.