Too much knee bend1. Revise basic drills.
2. Concentrate on a small flip of the feet.
Lack of undulation in the body1. Practice dolphin kick under water.
2. Practice dolphin kick under water arms extended above head.
3. Start the action by moving the head.
Only one kick per stroke1. Kick and glide when the hands enter the water.
2. Reduce the glide later.
Straight arm pull1. Learn 'keyhole' pull.
2. Scull with hands (out, in, out).
Arms fail to recover clear of water1. Practice over short distances to avoid fatigue.
2. Breathe by poking the chin forward close to the surface.
3. Recover the arms wide (thumbs down).
Timing1. De-emphasize kick. focus on 'head enters water before hands, head lifts before hands exit water'.