A large part of becoming a better swimmer is knowing how to execute a fast turn with proper technique. A good turn enables you to transition and move off the walls quickly, but it also contributes to better overall performance. 
Improving flip turns is an essential step to swimming faster and, often, winning races.
Here are the elements of a fast flip turn.
The approach
Accelerate into the wall. A fast turn begins with a fast approach - the more speed you have heading in, the faster your flip will be.
Don’t take a breath on your final strokes and don’t lift your head to look at the wall. Doing either of these will slow down your approach. Count your strokes and use the T line at the bottom of the pool so you know where the wall is and be able time to your turn at the correct distance without looking up.
Keeping your head down will also make it easier to tuck your chin in as you execute the turn.
The turn
Tuck your chin into your chest and keep your arms and legs close to your body. Eliminate unnecessary movements to maintain your momentum. The tighter you are, the faster you roll.
The turn is initiated by the chin and followed through by your core. Your arms will also assist in speeding up your turn. Keep your elbows close to your side and push the water towards your face to drive your turn as well as set up for the streamline.
To complete the turn, throw your legs straight into the wall so you end on your back instead of twisting on your side or flipping to your front while still on the wall. This reduces your turn time and puts you in a solid push-off position.
The push-off
The push-off is the fastest part of your swim, so it’s critical to maximize the power of your push-off and try to retain as much speed off the wall to optimize your time underwater.
Before you push-off, make sure both feet are firmly planted on the wall, about hip width apart. Try to land with your knees bent at close to a 90 degree angle to get good leverage for a powerful push-off, while minimizing your time on the wall.
Push-off on your back in a tight, streamline position before you start your dolphin kicks and twist to your front. By coming out of the wall flat on your back, you’re ensuring your trajectory is forward, not down towards the bottom of the pool or up towards the surface.
Improving your flip turn will require plenty of practice. Small improvements on these different components will add up, so perform a few drills to work on improving them individually.
More importantly, treat every transition in practice as if you’re in a race. Lazy efforts on the wall is the biggest barrier to good flip turns.
