How to do 
a sailboat, ballet leg, flamingo and double leg.

It all starts in the layout position: your body is horizontal, stretched and taut. You stay afloat by sculling with your hands, but also by stretching! 
You must be stretched tight from the tips of your toes to the top of your head! Your head must also be straight and stretched, with your chin pointing towards the ceiling. You can also stretch properly by pretending that an imaginary wire is pulling your head one way and your feet in the opposite direction. Try to make yourself as long as possible!

Start off in the layout position, as described above, then bend your leg so that the tip of your foot reaches the back of the knee of your other leg. 
Your thigh must be at right angles with the rest of your body, with the other leg fully stretched and your eyes looking at the ceiling. And that's it, you are now in the sailboat position! 

You must stretch out your leg without moving your thigh, forming a right angle between your whole body and your leg. But look out, this will apply more pressure! So, you must speed up the movement of your hands and keep your fingers tightly together in order to scull properly. Being fully stretched out will always help to execute these figures. The more you are stretched out, the lighter you will feel! Remember the imaginary wire. Now, it is pulling your head one way, your supporting leg the other and your raised leg towards the ceiling. A little tip. Never look at your foot! Try to keep looking at the ceiling, or even slightly towards the rear. Make yourself taller! 

A flamingo is a ballet leg, in which you also bend your supporting leg. Bring your thigh towards your chest. Imperative: your shin and foot must remain on the surface! Pull this leg towards you until the middle of your calf reaches your leg that is vertical. Sounds difficult? An image says more than a thousand words. Just watch for yourself!

From the flamingo position, stretch your folded leg until it is vertical, so that both of your legs are side by side. This means that all the weight will be on your hips! At this point, you really need strong support. Accelerate the movement of your hands, while bringing them very close to your hips, as if you wanted to put them under your buttocks, in order to be as efficient as possible. Your legs are now perpendicular to the surface, and your face must be out of the water. This really is a difficult figure. But it's perfectly feasible too! 
It obviously takes a lot of practice, but practice makes perfect, according to Virginie Dedieu!