Images from Arco Olympic Training Center, San Diego 1996

Order of paddlers from left to right: Recovery, Wind-up, Midstroke (power).
Think in at the feet, out at the shorts. Don't want to lift water by bringing the paddle back too far before the recovery.
Great to practice technique on flat water a couple of times a week.

Side View - Note forward tilt of torso, straight arms, knee position under flowery skirt.

These guys are using wing paddles, so they always move slightly away from the boat to catch "fresh" water.

Note torso rotation and arm position.

One visualization I like that I learned at this clinic:

Wind-up as if to spear a fish, maintain the box (elbows at ninety degrees), plant the paddle, unwind, recover. Keep the top hand above the bow the whole time (so you can see the bow under the hand).
Return to wind-up, pause 10% of the stroke.
This is a racing or power stroke, for touring just lower the arms and slow down.