Training Video: Locating the Enemy

Good stuff, self-explanatory. As true today as it was back in the 60’s.
To add: for hard targets to indicate, if you are using a reference point, you can indicate distance to the left and right of the reference point by the finger tip or knuckle method: raising you hand at arms length, hold up your finger tips or knuckles; you call out how many fingers or knuckles the enemy is to the left or the right of the reference point.
In a defensive position reference points should be marked on range cards.
In an advance, reference points should be allocated by the squad leader before each move across the next section of terrain – ideally from a vantage point, the squad leader will have the squad lined up looking out, and will call out the axis and any reference points. Works in open country, not in close country.

Observation and locating the enemy can be hard, and is crucial to further action. 

Finding the Enemy Part 1
Finding the Enemy Part 2

Live Hard, Die Free.