Leg flips. Put both legs over the same side of the ski. Place the blade in the water as the same side as your feet. Flip your feet to the other side of the boat. Repeat on the other side.
Paddle looking left for 10 strokes, then paddle looking right for 10 strokes. Work up to 100.
One and Done. Take one stroke and glide until the boat stops, take the next stroke and so on.
Catch
One-hand catch. In a stationary boat get into your setup position, paused before the catch. Remove your lower hand from the shaft and practice planting your blade with only your upper hand.
Two-hand catch. Same as the one-hand catch drill but grip the paddle shaft with both hands. Initiate the catch with the upper hand.
Open your upper hand on the drive. Looks like you are reaching forward to grab something in the air. Helps train a loser grip.
One finger drill: thumb to one finger no power paddle. Good for overall form work.
Efficiency
Stroke Count. Mark off a short course of 50 to 100 meters. Count your strokes. Work to reduce your stroke count by perfecting your stroke. Another approach is to measure how far you can paddle in 50 strokes and work to increase your distance.