A fly rod is flexible, giving you the ability to cast the rod and release energy through it to send out the line. To get the rod to release energy, you want the rod to stroke (or bend), then stop. Proper stroking and stopping of the fly rod will create a good fly cast with proper energy. Releasing energy through a fly rod is not necessarily strength-related. It’s more timing related. The practice is the best way to become good at timing your cast.
Fly anglers seldom need to cast more than 50 feet when fishing, but once you have mastered the basics, you can also try long-distance fly casting. It would be best if you learned to cast short (30 feet) first and then practice at greater distances.
You can’t learn fly casting from a book. It would help if you did it. The more you practice, the better you’ll become. Practice on a lawn or pool. Casting while fly fishing is not practice. Practice allows you to focus on casting fundamentals without distractions.
Grasp the fly rod firmly with your casting hand and place your thumb on top of the rod grip. When you learn to cast, keep the fly rod butt under your wrist and in line with your forearm. That way, the rod will remain in the same straight plane during your cast. If the fly rod comes out of plane during the cast, the tip wanders, and the fly line follows the tip, wandering and spoiling the cast.
You may hear other anglers talk about the angle of the cast: sidearm, 45 degrees, or overhead. You want to find a casting stroke in the most comfortable position for you, but eventually, you will use all these casting positions when you are fly fishing, so get used to them. The fly fishing casting principles remain the same for all casting positions.
To start, you will want to create short casts; aim about 4 feet above the water (or lawn). As your casts get longer, aim higher to allow the line and fly more time to reach the target. Learning to aim accurately is a hallmark of expert fly casting. It would help if you spent considerable practice time learning to aim and to hit targets on the lawn beforehand.
For this practice exercise, first, make sure you have the basic supplies. A fly rod, reel, and line outfit, and some leader, a tippet, and a fly will do. Grab your supplies and head to your backyard or open space like a park. You’ll need at least 120 feet (60 feet in each direction) with no overhead obstructions.
Take a marker or pen and mark your fly line with an indelible marker at 30 feet. The marker will indicate the length of line you have out when you cast. Then place hats or some other objects on the lawn 30 and 60 feet from where you will stand. The markers will help you develop the sense of distance critical in casting accurately to fly fish.
Thread the line off the reel and up through the line guides and out the tip-top of the fly rod. Tie a 9-foot leader onto the end of the fly line using the tube knot and tie a small piece of yarn to the end of the fly tippet.
Stand on the lawn with your feet slightly apart. Pull about 20 feet of line off the fly reel and lay it out on the lawn to the right of where you stand (to the left if you are left-handed). Ensure the fly line is drawn tight on the lawn and is not lying in S-curves, or it will not cast well.
It does not matter if you start by casting from the side or overhead; make sure it’s in a straight line. The sidearm cast allows you to watch the line and teach yourself timing and loop formation, so try that first. Using a horizontal side-arm cast, flick the fly rod tip forward from your right to your left (from your left to your right if you are left-handed), and watch the fly line form a loop and roll out to your left and then settle to the grass.
Using your arm and a flick of your wrist together (the way you’d throw a Frisbee backward and a baseball forward), cast the fly line repeatedly back and forth in backcasts and forward casts. Try to make the line form candy cane-shaped loops in both your backcasts and forward casts. Loop formation is the intent of your fly casting- the tighter the loops, the better the cast.
As you stroke, the rod back and forth, keep a firm wrist and stop the fly rod abruptly after each stroke. Stopping the rod allows the fly line to form a loop off the rod tip. It also allows the fly rod’s tip to turn over to unload energy into the fly line efficiently. The energy in the fly rod casts the line. It would help if you stopped the rod when making both the forward cast and the back cast to become a good fly fishing caster.
After casting sidearm for 15 minutes, or until you feel comfortable with the fly line and fly rod feel, try casting the rod at a 45-degree angle and then overhead.
Practice makes perfect when learning to fly cast. For those that are learning to fly cast, here are some common errors and how to correct them:
Problem: Backcast dropping to the lawn or water.
Fault: The fly rod tip is flopping over (pointing too low), sending the fly cast to the ground.
Correction: Stop the fly rod tip high. Keep a firm casting wrist.
Problem: Tailing loops.
Fault: Stroking the fly rod too hard or too soon.
Correction: Stroke more gently. Allow the fly line time to straighten out in the backcast completely before stroking the forward cast.
Problem: Fly snaps off with a crack in the backcast.
Fault and Correction: Same as for tailing loops.
Problem: The cast dies before reaching the target.
Fault: Underpowered cast caused by loose fly line by a floppy wrist stroke.
Correction: Tighten the fly line before the pickup for the backcast. Use a firm wrist stroke on the backcast and forward cast, and stop the fly rod immediately after the stroke.
Expert fly casting takes practice, but 15 minutes a day (every day in summer) can make you an expert caster in one season.
This article is courtesy of http://takemefishing.org/fishing/fly-fishing/fly-casting/fly-casting-basics/