Trading the ES is one of the traps on the road to the profitable trading. This market is overcrowded and one of the most complicated in the world, if not the most. All the around-the-market industry (brokers, educators, books) forces the beginner to trade this instrument. The smallish intraday margin (500$ per car) and the pipe dreams like ‘make 2points per day and you will be wealthy because of great liquidity’, and now the MES step in for undercapitalized.
My advice is to start the trading career on the other market, less competitive. If you are strictly directed to the US index futures, look at the NQ/MNQ, if you can trade European session look at the Euro Bund, but anyhow firstly became profitable trader of other market(s), not the ES. You must be boxer firstly, and think about champion's arena secondly, otherwise you will be in the knockdown in no time.