Ether tends to be defined by that which it is lacking. By its nature, it is the absence of properties rather than the properties themselves. It lacks fire’s warmth, so it is cold. It lacks the propulsion of air, so it is still. And it lacks the heaviness of earth and water, so it is light. Ether is also limitless and boundless, so it fills the whole of space.
Because ether is associated with consciousness, it is possible to bring more of the ether element into any yoga practice by cultivating more mindfulness and awareness. This can be applied to life "off the mat" by living a more conscious life, but it also relates to practice "on the mat."
In a more literal sense, noticing the space between breaths as well as the space around the body as it moves through asanas and holds them, can help the practitioner become more attuned to the ether that surrounds them.
As an element, ether is associated with the throat chakra (visuddha). This is because the throat chakra is connected with sound and communication, and it is through ether that sound is said to pass.