i tried day trading the ES for a while but gave up eventually because the intraday volatility and spread were killing me. so i switched to swing trading which i have found to be much more profitable. (for me)
from personal experience, i have managed 3 to 5 points a day (average, sometimes more sometimes less) over a 3 month period, starting with 1 contract. However, i am not a day trader, i swing trade the ES with a usual holding period of 2 to 3 days