Ralph Waldo Emerson said that Concentration is the secret of success in politics, in war, in business, in all management of human affairs Concentration of mind is supposed to be a good remedy for a lot of mental problems. Mantra recitation is one way of building up concentration. Writing Mantras or Likhita Japa is even better.:-

The word Mantra when broken up means Man (Thinking) and tra (freedom or protection) This means that the word mantra means protection from thinking by repeating a word or phrase over and over again which is called Japa..Mantra as a technique for regulating the mind.Therefore the literal meaning is “to set free from the mind & conditioned mental habits. Mantra is said to “save one from all fear”

Though this is an extract from a website, it is almost as if I have written it myself:-

“If you have an active, chattering mind, then mantra and or japa yoga are very useful tools for learning to control the meandering thoughts that keep you out of the present moment. Mantra has often helped me when my mind is racing out of control, thinking about something in the past or future. It has come to the point that when needed a mantra comes up in the back of my consciousness and I can choose to tune into it rather than the thoughts in my head. The mantra pulls me back into the present where peace always.”

Audible repetition is called vaikhari japa, while that done by whispering or humming is termed upamsu japa. The Mental repetition, manasika japa, is the most powerful; it requires keener concentration, for the mind tends to shut off after a period of time. The advantage of loud japa, which should be used with discretion, is that it shuts out all worldly sound and distractions. One should alternate when necessary, particularly when drowsiness sets in.

Likhita Japa or writing mantras over and over again is even more effective as brought about by these quotes from various websites:-

“Likhita Japa helps in all round concentration.”

“You can develop a wonderful power of concentration. “

“Observe and consider each repetition and you may notice that there is progress in concentration”

“The benefits of Mantra-writing or Likhita Japa cannot be adequately described. Besides bringing about purity of heart and concentration of mind, mantra-writing gives you control of Asana, control of Indriyas, particularly the sight and the tongue, and fills you with the power of endurance.”

“Likhita Japa can be particularly effective to curb the restlessness of the mind. This repetitive writing brings peace, poise and strength within.”

“People with Obsessive Compulsive Disorders (OCD) will find great benefit from this practice, since it engages the senses into the present moment without any great deal of discipline and effort.”

“In the Vaishnaviya Tantra it is stated: “Writing the Mantra with full concentration is one hundred times more beneficial and powerful than Japa chanting”

“Also while writing the Mantra, the chanter is forced to perform the concentrated Mental Japa and remembrance of the syllables of the Mantra which as described above is one thousand times more powerful than mental Japa. Therefore, Written Japa is one hundred thousand times (100 x 1000) more powerful than Vacika Japa or loud chanting.”
Thus the benefits of this Likhita Japa cannot be adequately described. Besides bringing about purity of the heart and concentration of the mind on the syllable form of God, Likhita Japa imparts the chanter with the power to control one’s senses, increases one’s power of concentration, memory and endurance. Recollection, Absorption, Meditation, Constant Rememberance and the Supreme Trance (samadhi) are the five progressive levels of Likhita Japa”

One can further use one’s imagination to build up concentration and break monotony. For instance one can write one word faster and one word with poise and alternate the pattern in the next line. Still better one can write one alphabet in capital and one in Small letters.This further builds up concentration of mind.

Variety in japa is necessary to sustain interest, avoid fatigue and counteract the monotony that can arise from constant repetition of the same syllables. This can be provided by modifying the volume. The Mantra can be repeated aloud for a while, then whispered, and then recited mentally. The mind needs variety or it becomes tired. People also use Rosary of 108 beads to aid concentration. This is a pattern that can be useful. I have used the mantra “Aum” but the pattern can be anything. Here L
Stands for loud W stands for whisper and M stands for Mind(in the mind)

Aum Aum Aum Aum Aum - L

Aum Aum Aum Aum Aum - W

Aum Aum Aum Aum Aum - M

Aum Aum Aum Aum - L

Aum Aum Aum Aum - W

Aum Aum Aum Aum - M

Aum Aum Aum - L

Aum Aum Aum -W

Aum Aum Aum -M

Aum Aum -L

Aum Aum -W

Aum Aum -M

Aum-L

Aum-W

Aum-M

Aum Aum Aum -L

Aum Aum Aum -W

Aum Aum Aum -M

This way 54 repetitions on the rosary are complete. One can repeat them again and 108 repetitions shall be complete and one rosary shall be over

The important thing to remember is not to let monotany set in.