Unless you are one of the very few, you will be casting with too much power. Every single person who I have taught I have told to cast with less power (repeatedly in fact and sometimes I have wished for a tape recorder). Flycasting may be about many things: straight paths of the rod tip, hauling speed, abrupt stops, increased sex-appeal, flip-flops, but power is not one of them.
In fact if you are having trouble throwing tight loops taking the power out will undoubtedly help.
When I distance cast I consider the rod arm to be responsible for the loop shape and the haul to be responsible for the speed. A tight fast loop will out perform all others. An over-powered loop will very likely become an open loop for the simple reason that it is very difficult to stop the hand abruptly when it is forced. When I want to cast further I concentrate on extended drifting and increased haul speed.
Hauling speed is what really counts here.
Of course you might not be interested in distance, maybe you only want a short cast; I'm still saying less power. On the MPEGs on this page I have about 10 yards of flyline in the air. Look closely at the amount of power, or rather lack of it.
This movement is the foundation of the overhead cast and one of the things you should regularly practice.
Another point of interest on these videos is that, although it often looks like I use lots of wrist when casting, I do in fact use very little during the stroke. If you look closely at the other MPEGS and Animated Gifs you will see that my wrist movement is applied after the stop and forms part of the drift. I find that with this minimal wrist movement I can force a deeper flex in the rod when distance casting, as well as a narrower stroke for shorter casts.
And finally I would like for you to look very closely at the hat in this picture; notice how it is slightly flattened backwards giving that all-important streamlined effect. Yet another important feature of the Arden Flip-Flop Cast.