Q: What is dhyana?

Ramana Maharshi: Dhyana is holding on to a single thought and putting off
all other thoughts.
Q: What is to be meditated upon?
R: Anything that you prefer
Q: Shiva, Vishnu and Gayatri are said to be equally efficacious. Which
should I meditate upon?
R: Anyone you like best They are all equal in their effect. But you should
stick to one.

Q: How to meditate?

R: Conentrate on that one whom you like best. If a single thought prevails,
all other thoughts are put off and finally eradicated. So long as diversity
prevails, there are bad thoughts. When the object of love prevails, only
good thoughts hold the field. Therefore, hold on to one thought only. Dhyana
is the chief practice.

A little later Si Bhagavan continued: Dhyana means fight. As soon as you
begin meditation, other thoughts will crowd together, gather force , and try
to sink the single thought to which you try to hold. The good thought must
gradually gain strength by repeated practice. After it has grown strong, the
other thoughts will be put to flight. This is the battle royal always taking
place in meditation.

One wants to rid oneself of misery. It requires peace of mind, which means
absence of perturbation owing o all kinds of thoughts. Peace of mind is
brought about by dhyana alone.

Later Sri Bagavan continued: When dhyana is well established, it cannot be
given up. It will go on automatically whether engaged in work, play or
enjoyment. It will persist in sleep,too. Dhyana must become so deep-rooted
that it will be natural to one.

Q: What rite or action is necessary for the development of dhyana?
R: Dhyana is itself the action, the rite and the effort. It is the most
intense and potent of all. No other effort is necessary

 If dhyana is gained, there is no need for anything else
Nothing is as good as dhyana
(Talks with Ramana Maharshi p.280f)