IMO, the best players are the ones who:
-Have superior hand reading abilities.
-Mix up their play a LOT, making it very difficult to read their hands.
-Are aggressive, but not lunatic aggressive.
-Don't make the big mistakes (bet sizing errors, horrible calls, etc) that the average player makes.
Those are just the first things that come to mind for me.
As for the differences between HU SNGs and HU Cash Games, there are a lot.
