I take countering orders to be, for example, using defensive against and attacking opponent, or vice versa. The first will give you a leg up if you are using counters, the second will nullify them if you are of greater quality in the appropriate area.
Other people will have different interpretations...
EDIT: Read up one reply, Tactician has gone into much more detail - I may disagree in minor details, but in essence I would agree with his summary.