There are four essentials of devotion or spiritual practice through love.
1. Non-stop
2. Non-demanding
3. Only-God-Reliant
4. God-Saint equivalence (if you have a genuine saint as per criteria specified earlier)

Love should be non-stop. There should not be any gaps. Wherever you are, Whatever you are doing, Whichever condition you are in, love should flow. Hindu says mind is the sole cause of bondage (worldly sufferings) and freedom (eternal bliss). External condition makes no difference. For example whether or not you have taken bath, even if you have some bodily ailment or bodily impurity, you remember God, in fact there is hymn which says ‘Remembrance of God purifies you from within (mind) and from outside (body)’.
In initial stages, it is very difficult to achieve non-stop devotion. The reason is we lack love for God and that is because there is no deliberation on qualities of God. How do you develop love for material person? Because of some of the qualities of beauty, softness, sweet talk or any other skill which you like. God has every quality that you are looking for. He can assume any beautiful form of any one you admire on this earth. You can always think of God in any form including that of any living or dead person or as per your imagination. Form is different from the personality that resides in it. You want God in that form and not that person. Person is always full of short comings while God is devoid of any shortcomings.. It is a similar case of two same looking twins but you love only one.

Further God is extremely kind and compassionate and loving otherwise he would not create this world in the first place. He does so many things for you because he treat you as his offspring. The body which you have is his creation. What parents did? They just enjoyed sex. Mother doesn’t even get to know what is happening inside the womb. I am not hinting that you disrespect your parents but realize the fact that it is God who is your real father and mother because he gives you everything including the body.

Respect and love are altogether different. Just as any working person respects his boss but loves his family, you too give respect to everyone but love only God. Don’t think everything is automatic. Everyone gets body including that of genes according to the actions of past lives. Who can do this unpaid job of accountant other than God? He does it out of his compassion otherwise no one would get anything! No birth, No happiness, Nothing! If you see it correctly, he makes the provision of breast milk and further all vegetables, cereals, wheat, rice, fruits and so on. And all this work in spite of the fact that soul loves everyone else except God. Soul is not ready to accept even the presence of God, yet God takes care of the soul through all his infinite lives. Think his compassion, think his kindness, think his love, you will remember him more and more.