Breaststroke may seem simple at first sight, but if you're looking for optimum efficiency, it becomes very technical. You're constantly trying to compensate for the upright position of the body, due to frontal breathing. It's the same as butterfly, except that the particularity of breaststroke is that it's propelled by the legs.
Swim with the body lying on the chest
Cut the surface of the water with the head during each cycle (except for the 1st cycle after the start and during the turn)
Complete your swim cycle with an arm movement and then a leg movement
Make simultaneous arm movements in the same horizontal position
Bring your hands forward together
Do not bring the hands above the hip line (except during the 1st movement at the start and the turn)
Do not raise your elbows above the water (except during the turn or the last movement before the turn or the finish)
Move your legs simultaneously (not alternately) and in the same horizontal position
Take the head out of the water before the hands turn inwards during the widest phase of the 2nd pull with the start and the turn
Have the feet turned outwards during the propulsive phase of the leg movement
Do not perform a downward dolphin movement except for the one authorised during the start and the turn
Do not flutter or undulate
Touch the finish or the turn simultaneously with the 2 hands separated (not superposed)
Do not stand on the bottom of the pool