Hi All
Namaskar

Elevating mind and self is the real emphasis of meditation practices.  

The importance of hatha yoga (ie physical postures) is that the body must be kept in good condition to allow for proper concentration and meditation.  So take care of it through proper exercise. Yogic postures are those inner exercises for the glands and hormonal system of the body.  Also, on the physical level is careful attention to diet and how one eats, including when not to eat and even fasting.

Intellectual knowledge is primarily an aid to personal understanding of the spirit of meditation and yoga.  This is also called jinana yoga (pronounced gyah-nah) and teaches the ideal of nondualism - that the Macrocosmic Manifestation is singular.  This is important in meditation because you identify your small self with the Universal. Perceptions of countless distinct phenomena arise through the limitations of our sensory organs.  Meditation attempts to experience the wholeness of everything and this comes from mental elevation and internal experiential feeling.  What we experience through the external sense organs is a relative truth.  What we experience through 'internal sensing' or meditation is that which is lasting within - the essence of existence.

In yoga the universe is a 'living' Consciousness and bears a relationship (direct and indirect) with every entity.  It is surely the best way of seeing and experiencing the world.  Meditation does not attempt to experience some dry void or nothingness or is done for the mere counting of breaths.  Rather it is a means of transcending the present level of consciousness and realising the oneness of the Universal Expression.  This is the spiritual emphasis.

In sleep and dream you could say you also transcend your immediate conscious world, but meditation is deeper than that and deals with the supramental or superconscious mind. We all feel we have an element of existence that is more than our ordinary self (whether awake, dream or sleep). In simple terms we want to reach our inner self.

Theory is one thing, but through the practice of meditation this is where the real experience comes.  That practice may take some time to be established in daily life, but is necessary.  Physical well-being and intellectual knowledge of yoga supports the practical day to day lifestyle and practice of meditation.  The basis of meditation is ideation (focus), internal feeling and mantra (subtle vibrational root sounds of the mind and psychic structure of the body used to elevate the mind in meditation).

In that practice and lifestyle, proper action is important also (as is proper thought).  This is called karma yoga in Sanskrit.  It means to regulate how you act in the world.  Karma yoga is acting with integrity.

There is a categorisation of yogic practices called raja yoga (pronounced rah-jah) meaning literally "royal yoga" and it is also known as classical yoga.  When you mingle with meditation practitioners long enough, you can expect to hear them refer to the eightfold path, as codified in the Yoga-Sutra of Patanjali.  This is the standard work of Raja Yoga. The eight limbs of yoga are:

- external moral/ethical discipline 
- internal moral/ethical strength 
- yogic postures 
- proper breathing 
- withdrawal of senses from the external world to internalise your consciousness for meditation 
- concentration, or extended mental focusing, fundamental to yogic meditation 
- process of meditation, the principal practice of bringing your mind to ideate on Oneness 
- experience of unitive consciousness so as to feel inwardly one with the feeling of Infinite Peace

All these aspects are useful to the meditation practitioner.  They are tools to the actual meditation practice.  The experience or experiential is what is counts.  This is emphasised with group participation in meditation collectives.