Gayatri Mantra appears in the Rig veda (3.62.10), attributed to the great Sage Viswamitra. This mantra is composed in a very auspicious metre named Gayatri (8 syllables x 3 lines) and hence the name Gayatri Mantra, the original name being Savitri Mantra. There are many Gayatri Mantras in Hindu scriptures, but Savitri Mantra is of special significance and superiority according to the Gita and endorsed by the Upanishads.
Japa Mala is a very personal spiritual instrument and hence should be treated with care and respect. Japa Mala should not be exchanged with another person, not placed on the ground or thrown around. It can be worn on your neck or kept safe in a special type of bag. This bag protects the mala and used properly ensures your index finger does not touch the beads while chanting. The index finger represents your ego and a mind looking outside for faults blame. A conscious effort not to touch the Japa Mala with your index finger, reminds you, the practitioner, to be mindful of your own ego that might come in the way of spiritual progress.
What are the factors for Japa (mantra repetition) to be successful?
The first is your connection with your Devata (god) - how intense is this connection and how much faith you have. The Devata can be your Ishta Devata (favourite deity who you pray on all occasions) or a 'functional' god who you pray to based on your situational goal (Example, you may pray to Lakshmi for wealth and prosperity today, and to Shiva for long life tomorrow). The mantra you chant can be related to your favourite deity or the functional deity - please remember that these two are equally beneficial and one method is not superior to the other.
Being religious might help one to achieve growth externally, being spiritual goes beyond that to achieve inner growth. Mantra Japa (Repetition of a Mantra) is one such spiritual practice that achieves inner growth in addition to external results. Japa is also equated to a sacrifice one does with one's own prana (vital energy) through chanting. In Bhagavad Gita, Krshna exemplifies the importance of connecting to Ishvara (God) through chanting by equating himself to Mantra Japa.