a great way to practice trading methodology on the YM is to trade DIA while you are learning.
DIA, at $1 per point is like a mini-mini-dow.
personally, i traded DIA for 6 months before i made a YM trade. it's a great way to develop a trading system. with paper trading, you eliminate "ownership" emotion, and thus it's somewhat unrealistic. It's also unrealistic as to fills and slippage. I have found that YM actually gives slight better fills than DIA, so if u can develop a system that works on DIA, it will work on YM.
the other major point, imo is not to get overleveraged. if you have a 50k account, and you are trading 25 cars (contracts), you are completely nuts. No matter how sound your trading methodology, very few people can be disciplined when that highly leveraged.
i don't think there is any other trading vehicle that offers the return on capital potential, on an intraday basis, than the YM does.
i, frankly, love it.