I ve walked as far as 50 or 100 feet to the next rising fish by false casting the entire distance. If a fish shows itself in a rise form, you are instantly ready to put the fly on the water. Many people incorrectly try to use false casting to distance their cast by putting lots of extra rod energy into their final presentation cast. It is more efficient to go through your false casting, then open up your line hand slightly on your forecast, which allows the line to shoot slightly from your loaded rod. This will easily get you an extra 10 or 15 feet on your cast.
Timing is the key factor in good false casting.
Do not allow your line to come totally straight. This causes the line to be pulled downward by gravity and the rod to unload. A good way to practice false casting is to turn sideways so you can watch your line unfurl to the rear. Remember to use the same casting energy to the rear and the front. One of the most common problems fly casters face is to underpower the backcast and hammer the forecast.