Judging distance (without a laser distance meter)
The Progressive method of judging distance is still the best. This is done by sighting an object (tree) down the side of the fairway, which is reachable with say a no. 9 iron. Then you pick out other objects that are progressively closer to the target. Each segment between the trees can represent the distance between club selections. Each sighting progresses from the original 9 iron to; as an example the 8, then 7, 6, until you are at the object that you estimate is level with your target. You have now arrived at the correct club with which to reach the green.
Whenever you are playing a shot have in mind the target and the line to it.