One of the best ways to invoke Goddess Tara is by chanting the sacred Tara Gayatri Mantra.
It is a Mantra for protection and good fortune, asking the Divine Mother for her grace and guidance.
Revered for her protective nature, Goddess Tara represents protection, wisdom and is the second of the ten Mahavidyas.
In Shaktism and Shaivism, devotees regard Tara as a fierce yet compassionate manifestation of Parvati or Shakti.
Tara Gayatri Mantra follows the Gayatri meter and responds quickly upon starting the Mantra Sadhana.
Chanting this along with other Tara Mantras fulfils all your desires, gives you courage and inner strength, liberates you from hidden fears and the cycle of suffering, and provides protection.
Tara worship can also be seen in the tantric and Buddhist Vajrayana traditions.

Tara Gayatri Mantra
ॐ तारायै च विद्महे
महोग्रायै च धीमहि
तन्नो देवी प्रचोदयात्॥
Om Tārāyai Ca Vidmahe
Mahograyai Ca Dhīmahi
Tanno Devī Pracodayāt॥
Meaning:
We meditate on the Goddess Tara
The greatly fierce one (symbolising her power), we contemplate on you
May the Goddess Tara Devi guide our intellect.
How Many Times to Chant this Mantra
If you are doing Mantra Sadhana, the prescribed Japasankhya is four lakh repetitions in 40 days (one mandala). One can also choose to recite 1008 times daily till the wishes are fulfilled. Following all the formalities of Mantra Vidhana for chanting this Mantra is a must for Sadhana.
For regular worship of Tara, one can chant the Tara Gayatri Mantra 16, 27, 51 or 108 times.