The person experiencing obstacles should repeat the Pranav Om ॐ three times, instead of one as is normally done. All mantras, including the Gayatri Mantra have their origin in the Ever- Existent Brahman, the Cosmic Sound or as Christians call it the Word.
The practitioner has to concentrate on the Om Beej and chant it slowly while breathing, in and out. Then while Chanting the Gayatri Mantra, he has to imagine that the Cosmic Vibrations of the Mantra are leaving his head and meeting and dissolving the obstacles. If the obstacles are people, then the Vibrations are entering their heads and dissolving the opposition or enmity.
This type of Gayatri Chanting can also be compared to Vashikaran, Akarshan and Mohini Mantra Practices. The practitioner should not count the number of chants and chant for about 10 to 15 minutes as long as he is fully comfortable while chanting the mantra.