I had written this up for a group I plan to help learn to fly cast...either for the first time, or to help some infrequent flyfishers improve their casting.
Now, I am NOT a certified fly casting instructor, and I have never received any professional instruction. This are just some tips that I've learned over the years of teaching myself, that I think are key to starting out and getting comfortable with flyfishing and fly casting quickly. Hopefully this is quick and easy enough for a newbie to digest and to get started with confidence.
-Remember, you are casting the LINE, not the lure.
-In order to cast the line, you load the rod and allow it to transfer that energy to the line.
-The generally-accepted backcast is a "10-to-2" (clock) rod position movement. You want to feel your rod load (bend). The key is a smooth acceleration between the 10 and 2 position, then a VERY abrupt STOP. The abrupt stop is what causes the rod to transfer the energy to the line.
-A "false" forward cast (one where you are not delivering the fly to the target, but simply lengthening the amount of line you have in the air) is a reverse of the backcast, except the weight of the line unfurling behind you starts to load the rod first and then you accelerate forward and abruptly stop at the 10 position (like chopping wood with an ax). Let the weight of the line moving forward out in front of you take more line out thru the rod's line guides.
-On your final forward cast (delivering the fly to the target), stop the rod at the 10 position, let the line shoot forward, and then slowly drop your rod tip towards the target as the fly falls to the water. If you have trouble with your leader/tippet not straightening out at the end of the cast, you can use your line hand to stop the shooting line just before it runs out of energy. The line will stop and the remaining energy will be transferred to your leader& tippet, moving them beyond the end of the fly line.
-Keep your wrist locked in position while casting.
-When casting, move your rod in a straight line forward and back.
Once you get comfortable with the above, you are ready for an advanced but very important and useful upgrade to your casting. It incorporates a "haul", which can be a single haul (used in either the forward or back cast) or double haul (used in both the forward and back cast). The double haul is no more difficult to learn than the single....so go for it.
The premise of the haul is pulling down on the line in your line hand at the beginning of the forward and/or backcast to create additional tension and rod loading, thus increasing line speed and resulting in shooting the line further. You pull down on the line at the beginning of the cast, as I mentioned, pause briefly as the line passes you, then raise your line hand back up to starting position as the line extends out on the other side of the rod. At this point you can also release more line into the cast if you want to. This technique is particularly useful when casting into the wind, or you are casting heavier flies, or if you are just wanting to get that little extra distance to reach the fish.
Burn these things into your mind. It may sound complicated, but with just a bit of practice, it all begins to flow together and come more naturally. Pretty soon, you are just doing it without even thinking about it. Kind of like driving a car. Remember how overwhelmed we were when we first started driving? So much to know and details to pay attention to! Traffic and street signs, other drivers, watch your speed, whose turn is it at the stop sign... where's the gas, where's the brake!
Anyway...those interested in reading about the myriad techniques in flycasting, you can search instructional videos on YouTube, or read the articles here (additional article headings are on the left column on the page):http://www.sexyloops.com/flycasting/tbasic1.shtml