No matter what type of fly caster you are; no matter how much you lean towards the poet type, sooner or later you'll decide you want to cast far. And the farther the better.
This exercise is a first step towards developing the skills you need to gradually add inches to your average distance.
Nothing and nobody. Just you and the basic element you've used in all the exercises and games: a tag (piece of wool).
Immediate: to be aware of how much line you can handle and then progress gradually from there. To get used to repeating short, equal sequences in long casts. To practice essential technical aspects in the execution of long casts.
Medium term: to increase your average distance 1 yard.
Long term: to increase your average distance three yards.
Very long term: to be admitted to the fantastic 30-yards-with-a-WF-5 club.
Start with some 12 yards of line stretched out on the ground. Pull another yard off the reel. You can measure it from your right shoulder to your left hand with your left arm stretched out. That's approximately a yard. Make two false casts and shoot this yard. Pull off another yard and do it again. The idea is for the line to land in a straight line with no slack. As soon as you make a heap or there's slack in the line when it lands, you penalize yourself three yards of line. That is, you reel in three yards and go on from there.
Make a special effort to control the force exerted with your casting hand. Concentrate on the fundamental parameters for long casts: straight path, vertical loop and fast line-hand.
Your double haul has to be almost perfect. If it isn't, you need to practice it separately.
It's already hard enough when you start pulling off yards and yards. Better leave it at that.