
Remember that where the rod tip goes, the line will follow - so you can change line direction while the line is in the air.
There are two methods:
When you cast a fly-line you can rotate your body as you cast. So if you were nymphing and casting your line upstream, you might reach a point where the line is below you. Wait till the line is tight and then do a back-cast, rotate your body 45 degrees and do the forward cast, then another back-cast, then turn to face the direction you want to fire out your fly and do that.

As with any cast the line must be straight before you begin, even if it means retrieving some line. Now the line is straight, bring the rod-tip back behind your shoulder and roughly pointing to 2 o'clock - do this slowly it is not part of the cast. Once the rod is in position wait till the line has dropped straight down directly off the rod tip - this step is vital to achieve a good roll cast. It allows the line to be ‘gripped’ by the water, which loads the rod. Once this point has been reached go into a forward cast as usual, (start slow, finish fast, stop dead). The line should unroll out in front of you, and once it has, go straight into a normal back-cast. Of course if you had no back-cast room, the roll-cast is the only alternative to delivering the fly, and it is a very effective alternative.
The roll cast is an absolute necessity to learn.
It is the easiest way to reposition the line for another type of cast. It is the easiest way to lift a sinking line, or weighted nymphs, up and onto the surface to cast. It is the easiest way to cast when there is no room for a backcast.
For a wonderful demonstration and tutorial of the roll cast see this video made by the Grand Dame of casting Joan Wulffe. It is the best I have ever seen. (As a footnote, if you still think power and strength are part of casting, watch Joan probably in her mid-sixties, showing just how wrong this notion is.
Sometimes finding room to cast is not easy and wind can be a problem, so you need to add a few variations to your casting repertoire.
Too obvious? But too true!
You do not need water to practice casting, except for the roll-cast). A local park will do nicely, if you have not got a river or lake handy.
Tie a few strands of wool onto the end of the leader – it helps to see where the ‘fly’ is going, and mimic the way a fly feels on the end of the leader.
Take a plate with you to use as a target as you move about. I used to start short and when I could get the fly within about 10cm circumference 4 casts out of 5, I would move back three paces, and so on. Try casting into, with and across any wind or breeze, moving in a circle around the plate.
I still practice regularly, especially if I have got a new rod or fly-line, or am going to be doing some distance casting, say salt water fly-fishing.
The last place you want to practice is when you are on fishing water – it is a huge waste of that precious time. Get your skills sorted out at the park, and have a much more enjoyable time on the water.
There is some practice you can do for fly-casting, without a park or water and it will help teach your muscles what is required during a cast.
Grab hold of a ruler at one end, fingers curled around it, thumb pointing up. Start with the ruler at nearly arm’s length, the ‘tip’ of the ruler pointing towards the ground about 3m (a rod length) in front of you. Pull your arm back, start slow, finish fast, so your hand is just behind your head and above your shoulder, and come to a screeching dead stop with your thumb pointing to one o’clock. Pause, and count “one potato, two potato”, then bring your hand down so it is just below your chin about a forearm's length from your body, and come to a complete stop with your thumb pointing to 11 o'clock. Repeat, often. Using a mirror is a great help too.
It helps give you ‘muscle memory’ - it works - and you can do it anywhere.
Too blow my own trumpet a little bit here; I have heard quite a few people say something along the lines of, “that was a lucky cast Bish!” when I have managed to drop a fly into a gap in a particularly nasty bunch of scrub and have it drift free, just as I wanted it to.
I have thought about coming back with the famous reply of Jack Nicklaus the very famous golfer; a person in the crowd once called out when Jack had sunk a particularly tricky putt, “Lucky shot, Jack.”
Jack replied, “Ya know the more I practice the luckier I get”.
There is no easy, quick, “just 5 minutes a day and you will be casting like a Pro in seven days, but wait...”, way of learning to cast well. If you want to become even a halfway decent fly-fisher and you are not prepared to invest some of your time in casting practice then put this book down and take up computer games or something equally injurious to your health and mental well-being. Ah, I feel much better, now where was I?
Yep, back on my hobby-horse again, but there is method in my nagging, and here it is - a list of things that make a cast just right, so now you have something to aim for.
There are many excellent articles on casting, basics, advanced, and specialty casts, on the Sexy Loops website. It is one of the best resources on the web.
Here are 28 very good fly-rod casting hints, from Midcurrent an excellent Blog and website on fly-fishing in fresh and saltwater.
Once you have got the basic casting techniques sending a line pretty much where you want, you can begin gaining greater distance by learning the ‘double haul’. I am not going to try and explain it; an excellent article on this is here.
For an excellent video demonstration of the ‘double haul’ see this.
Once you have made the cast, controlling the line on the water becomes the priority.
For an excellent article on line control and ‘mending’ with tremendous illustrations
see this article:
“A good friend of mine, who has been a guide for many years, always draws a
distinction between those clients who can cast and those who can actually
fish. (He maintains that the former outnumber the latter by a wide margin.)
Casting only helps you throw the line through the air. But the fish don't
live in the air. They live in the water, and the water is usually moving.”