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.
Do not to cross the Meru while chanting.
A second rule is not to cross the Meru during chanting. Japa Mala has a bead that stands out, called the Meru (same name as the spiritual mountain). One starts to chant starting with the adjacent bead and ends with an adjacent bead on the the other side of the Meru - please be reminded not to cross the Meru while chanting. You need to sit on a proper seat for chanting, ideally on a seat covered with a red cloth, in a comfortable position. If you have enough flexibility, you may sit in Padmasana (lotus pose) or Sukhasana (a cross legged comfortable pose). The body should not come directly in contact with the floor - hence atleast a towel is recommended on the floor if not a seat. If you need back support, you may sit in a chair or even lie down while chanting, as required. Again please be reminded that the rules are guidelines for the best results and what is important is the attitude with which one pursues the practice.
You may chant mantra multiple times a day, each time using a Mala of 54 beads or 108 beads.
A place which is quiet and free from disturbance is chosen for Japa. You may choose the space around the altar at home or any other corner including one in the bed room. You may choose to face North or East or North East while chanting in the daytime. You will face North while chanting in the evening (after sunset). There are four auspicious time slots for you to chant, each separated by 6 hours in a 24 hour day. These slots are around Sunrise (7am in Singapore - considered to be the beginning of the day), after noon (1pm), dusk (7pm) and midnight (1am). You may chant multiple times a day, each time using a Mala of 54 beads or 108 beads. In a series of chanting cycles, Pranayama need not be repeated in every cycle as the mind would already be in a calm state. Each time you may select the same or different mantra or method (loud, soft etc.). Please note again, that if you make a mistake in between or the mind wanders, continue the chanting after realigning to the process joyfully. You need not entertain any feeling of guilt, fear or anxiety of getting it right during chanting. Please surrender to your mantra and the process - it will help you get better each time.
If you have no access to a Japa Mala or you want to a bigger challenge, you may learn to use your palms and fingers for counting instead of a Mala. The process need to be learned orally and hence not documented here.
Note that Mantra Japa has a goal and it should be declared upfront in as much detail as possible (one or more goals). You could ask for health, wealth or anything worth achieving. Pursuing wealth is a noble goal as long as it is guided by Dharma and you fulfill the expectation of Dana (charity).
Chanting calms you down and helps you focus your mind, in addition to delivering other benefits - achieving the specified goal, strengthening the mental faculty, gathering merits etc. The intention to connect with Ishvara and the act in itself will being benefits to you, right from the beginning.