So far it seems we have:
1) Not stopping the rod at 10 and/or 2 (stroke too open, loss of power, open loop / Sean, BigDave, etc)
2) not waiting for the backcast to extend (timing, loss of power / Bigdave, striblue, etc)
3) elbow not in line (tip travel not in a straight line, tailing loop, line collision / Striblue, Frenchcreek)
4) stopping a spey cast too short or too high (tailing loop, line collision, loss of power / Fred)
5) over-thinking (soloflyfisher, Rimouskis)
6) creep forward before making the forward cast (loss of power / DbleHaul, Juro)
We can assume these traits are common to moderately experienced casters, since thatís what we see most often.
So I am going to stop this right here and ask for the above, what advice or methods (tricks) would you offer to these people to correct the 6 observations, if they asked?
I'll start with creep. One of my favorite metaphors for correcting creep is the batting champion metaphor. Consider Barry Bonds waiting on a change up. Not high inside heat, nor a low fastball - but a change-up, a pitch designed to make you think it's fast when it's really slow. Provided he isn't fooled, which he rarely is, he must feel like he has time to check his watch, tie his showlaces, and think about his investment options by the time that ball finally comes into range to be swatted out into San Francisco Bay.
If his bat moves forward, his stroke is shortened and he becomes a slap-hitter instead of a home run slugger. Likewise, if the rod does not "stay home" until the backcast loads it, the full amount of available energy is not leveraged into the cast.
This is essentially timing and rod position. I ask the question "did you see A River Runs Through It?". Have never gotten a "no" yet from someone with a flyrod in their hand. Well in that movie, the preacher sets the metronome for a four count... click, wait, click, wait. He instructs the boys to stroke only on the alternate beat. I then ask the caster to cast, calling out a four count with two strokes (one on every other count), called out loud. Then I tell him to extend the line, pointing out that the longer the line, the longer the wait. It usually results in their longest cast ever.
Seems to work pretty well, until the pod comes over the flat when a whole 'nuther kind of patience is necessary