Training and Intel.
If your soldiers know how to fight and who to fight, that's a pretty fucking big advantage right there.
ZephrC said:
Funny how drastically people tend to underestimate the value of numbers. That would probably be my second choice. Sure, there are examples of well trained, well equipped, highly motivated soldiers standing against superior numbers, but those are rare and almost always exaggerated. In reality 2:1 odds are a huge point in your favor. Even 11:10 odds can decide a battle.
Russia, The Second World War, 28 million dead, destruction and poverty - all because we had a lot of people who wanted to fight but not that many who knew how to fight.
In other words, even with such a colossal strength in numbers, the Second World War marked the most horrible, human-life disregarding bloodbaths for our army.
http://en.wikipedia.org/wiki/Battles_of_Rzhev
Sure, big numbers are a huge advantage, but they can easily lead to total disregard of human life.