If you have limited torso rotation that prevents you from finishing the stroke near the stern, protect your working-side shoulder by dropping the elbow of your working arm to your hip, and straighten the non-working arm across the kayak.
In the learning stage, watch the blade through the water but ultimately perform the stroke with the head facing the direction of the turn. This allows greater torso rotation at the set-up.
Hold an edge throughout the stroke for a tighter turn.
When used with an edged kayak, maintain a slightly 'climbing' blade throughout the stroke for support.
If feeling unsteady while edging, use a light skimming stroke with the back of the blade (roll your knuckles down) when returning to the set-up position.
Alternate the stroke with a reverse sweep stroke on the opposite side to turn your kayak around in more confined spaces (e.g. narrow creeks, rock gardens and sea caves).
Use the prevailing wind to improve the efficiency of the turn.
Time the stroke to coincide with wave crests passing underneath the centre of the kayak (i.e. when the bow and stern are out of the water).
Move your hands up the paddle so that the working blade is further extended. This provides more leverage for the turn.