I wrote a little bit about Mongol arrows and archery. The Mongol Keshik, there were an elite bodyguard type of group. And a little bit about the success of Genghis Khan. This was one of my earliest answers, so it isn't formatted particularly well.

Timothy May's The Mongol Art of War explains in minute detail the tactics of Mongol warfare. I would suggest giving it a read for a very in depth explanation.