Often we practice positioning in comfortable, uncompromised positions. Practised repeatedly, without attention to detail or rest, skills can often become undefined as fatigue on compensation creeps in.
When we look at Dance in particular, there is nothing you can do to improve more rapidly than practise the art form itself. However, there are some accessory exercises with a many progressive variations that will allow for great strength of positioning and precision of movement to be gained.
With a retiré, for example, Dancers can often lose feeling and sense of where the flexed and abducted hip joint resides in the position. Therefore, we can use variations of this exercise, with the help of gravity as resistance, to ingrain the movement pattern of this nature.