Re: How to roll cast farther???
I am fishing the same waters lately. Like cliff said, lift you casting arm straight up and maybe slightly to the side. Lift it to where the line is now hanging slightly behind you, then whip but try to stop at 10:00 to straighten the line then drop the tip.
I usually peel out a bunch of line and shake the tip to get it all out on the water, then I do what I just described.
With heavier flies, you have to speed up the first part to get the fly to the surface.