So I guess the only thing remaining is more Spotting markers, unless you stack all your units into groups and are lucky with the spotting attempts.
Remember that a unit that is marked Fired or Moved is automatically spotted, thus you don't need to make spotting attempts on them and you don't need to mark them with separate Spotted markers since the Moved and Fired markers imply that they are visible to any enemy with line of sight.
Not sure if this is causing you to have more spotting attempts or not, but generally I don't make many spotting attempts. Usually I'll wait until the enemy moves or fires first. When I do need to spot it is usually only my leaders making the attempts since a failed spotting attempt from a leader doesn't "waste" any potential firepower for a later impulse.