Constant remembrance of God, and how to achieve it?

Constant remembrance(Smarana, dhyana, or abhyasa of God) is not 'thinking of God every second', which is impossible for the restless mind, but cultivating a deep, natural undercurrent of awareness of God's presence in the heart, which flows alongside all duties.  It is not just when you sit in meditation, but also while living, working, and interacting with others.  This is not merely the mechanical repetition of God's name, but an inner state of feeling connected to Him.

Smarana is often described as an unbroken stream of thought directed towards the Divine, leading to a constant state of awareness. The Puranas also present examples, such as the liberation of Kamsa and Shishupala, who constantly thought of Krishna out of animosity, to demonstrate that continuous mental focus on the Supreme Lord can lead to liberation, even in unusual contexts. 

Dhyana in Sanskrit comes from the root "dhyai"-to think, to contemplate. It is a deep concentration of the mind on the Divine, so steady that distractions fade away. It is also not mere thinking, but stilling the mind so that the inner self shines. 

Abhyasa means a faint reflection, or subtle remembrance of the Divine that remains in the heart, even outside meditation. It also means 'not full concentration, not deep meditation, but gentle awareness that "He is there". It is the bridge between meditation and daily life. Even when the mind is engaged in family work, a subtle undercurrent of God is felt. 

Lord Sri Krishna in Bhagavath Githa Chapter 8, verse 14 says:

                                  'ananya-chetāḥ satataṁ yo māṁ smarati nityaśhaḥ

                                   tasyāhaṁ sulabhaḥ pārtha nitya-yuktasya yoginah'

He is easily attainable for the Yogi who constantly remembers Him with an undivided and focused mind, being absorbed in HIM.

This describes the path of bhakti-yoga, emphasising that a pure, devoted mind, free from other thoughts and desires, is the way to easily achieve the Lord.  Srimad Bhagavatam also illustrates this through figures like Prahlada and Dhruva, whose unwavering devotion and constant remembrance of the Lord are highlighted as paths to liberation. This practice involves an unbroken mental focus on the divine, encompassing meditation, listening to stories, and remembering the Lord's glories and names, ultimately leading to spiritual advancement and liberation.

                           'Gurur Brahma Gurur Vishnu Gururdevo Maheswara

                            Guruh sakshat Parabrahma tasmai sri Gurave namah'

The guru is Brahma, the guru is Vishnu, the guru is Mahesvara, the guru is the self-revealing limitless Brahman. Salutations to that revered guru.

The above sloka in the Guru Gita, as found in the Skanda Purana, is traditionally attributed to a dialogue between Lord Shiva and Goddess Parvati. Lord Siva explains to Matha Parvathi that the guru should be seen as the embodiment of Brahma, Vishnu and Mahesvara and ultimately as Parabrahman itself. 

Hindu philosophy places the Guru-Master as essential for spiritual progress, often above direct deity worship, because the Guru embodies, channels, and unfolds the wisdom and grace of Brahma, Vishnu and Maheshwara in accessible form.  The Guru is revered as the means by which God's blessings, knowledge and liberation are truly attained. Guru gives us Gyan (knowledge) about God and about spirituality.  Guru is the only power that can extricate ordinary people like us from the intricacies of the path.

It is therefore essential that the guide we select must be one of the highest calibre and worthy of the task of tearing off the intricacies at a glance with the aid of the extraordinary power at his command. He must have his access up to the farthest possible limit and possess the power of Yogic transmission (Pranahuti). Such a man we must seek as our guide if we wish to achieve complete success.

Sri Ramchandraji, founder of Shajmarg(simplified Raja Yoga suited for modern life), is one of the real Masters who emphasises the following examples of how one can remember God constantly during his lifetime.

While doing a thing, think that you are not doing it for yourself, but for your Guru/Master, or rather think that your Master Himself is doing it for Himself. While at the breakfast table, you must think that your Master and not you is breaking His fast. When you go to the office, think that your Master is doing all the work. While returning from the office, suppose you see an attractive dance on the way, your eyes are caught by the charming appearance of the dancer. Your thoughts seem to be diverted for a while. Then also think that your Master and not you is seeing the dance. You will at once lose curiosity for it, because your Master’s power will begin to flow into you to relieve you of the temptation.

When you come back from the office, your children rejoice to see you after so many hours. You enjoy their merriments too, and it is but natural. Your attention is, for a while, diverted towards them, and you feel a bit away from the sacred thought. What you are to do then is to think that the Master in you is Himself enjoying, and they are the children of God, who are entrusted to your care and whom we have to provide for and look after as if duty-bound, we are then serving His children and thereby God Himself. We shall thereby get rid of undue attachment too and shall thus remove one of the greatest obstacles from our path.

If you are chatting with your friend, think that your Master, not you, is talking to him. While walking, think that your Master himself is walking. During meditation, if you entertain the idea that not you but your Master Himself is meditating on His own form, it shall bring about excellent results. Similarly, you can adjust yourself in your daily routine work.

If you cultivate this feeling and maintain the outlook that your Master is doing everything in your place, you shall not only be in constant remembrance all the while, but your action will cause no impression whatsoever, and very soon you will cease making further Sanskaras. A man leading this kind of life in no way becomes an obstacle to others in this world. The life of such a person is beneficial to both himself and the world.