Well, there be lots of discussions on how to whack the Mongols as the English using yeomen longbowmen with stakes at bridges and on hills and even in cities and using hobilars to ride down the Mongols faster units, and using cannons, but you really will need to have at least a mediocre general or even your best troops will soon bolt from the fearsome Mongols. One vital reason to launch a crusade and succeed is to get Knights Hospitaler because when they are promoted to gold level they can do some damage to Mongols and even Timurid elephants if they charge into their butts. Without some special high chevroned units and good generals you will have to use "human wave" attacks - so start spamming troops.