"Spirituality is not to be learned by flight from the world, by running away from things, or by turning solitary and going apart from the world. Rather, we must learn an inner solitute wherever or with whomsoever we may be. We must learn to penetrate things and find God there." Meister Eckhart (12th Century mystic)
Navaratri means nine nights, an auspicious time of the year to invoke Durga. Why not undertake a sadhana at this time? Sadhana is a "goal-oriented spiritual practice." It requires both love and discipline.
Hindus throughout the world are engaged in this practice through rituals and a mind-set. Why not use this time to be part of the field and be carried by the massive devotion taking place worldwide? Catch the wave. Ride the tiger.
That's a good starting point. This mantra develops the absolute reality formula as OM, the seed syllable of Durga (duṁ); the devotion to this aspect of the Shakti (durgāya); and Namaha the veneration we are offering.