It would be a gross mistake if you consider Bhakti as merely a stage of emotionalism, while it is actually a thorough discipline and training of one's will and the mind, a sure means to intuitive realization of God Almighty through intense love and affection for Him. It is a means to thorough apprehension of the true knowledge of Reality, beginning from the ordinary form of idol worship right upto the highest form of cosmic realisation of your oneness with Him. You can achieve this by following the eleven fundamental factors which Sri Ramanuja had prescribed. They are Abhyasa or practice of continuous thinking of God; Viveka or discrimination; Vimoka or freedom from everything else and longing for God; Satyam or truthfulness; Arjavam or straightforwardness; Kriya or doing good to others; Kalyana or wishing well-being to all; Daya or compassion; Ahimsa or non-injury; Dana or charity; and Anavasada or cheerfulness and optimism.
People put a question: "How can we love God whom we have not seen ?"
Live in the company of saints. Hear the Lilas of God. Study the sacred scriptures. Worship Him first in His several forms as manifested in the world. Worship any image or picture of the Lord or the Guru. Recite His Name. Sing His glories. Stay for one year in Ayodhya or Brindavan, Chirakut or Pandhapur, Benares or Ananda Kutir. You will develop love for God.
Every act must be done that awakens the emotion of Bhakti. Keep the Puja(worship) room clean. Decorate the room. Burn incense. Light a lamp. Keep a clean seat. Bathe. Wear clean clothes. Apply Vibhuti (sacred ash) or Bhasma, and Kumkum on the forehead. Wear Rudraksha or Tulasi Mala. All these produce a benign influence on the mind and elevate the mind. They generate piety. They help to create the necessary Bhava or feeling to invoke the Deity that you want to worship. The mind will be easily concentrated.
Practice of right conduct, Satsanga, Japa, Smarana, Kirtan, prayer, worship, service of saints, residence in places of pilgrimage, service of the poor and the sick with divine Bhava, observance of Varnashrama duties, offering of all actions and their fruits to the Lord, feeling the presence of the Lord in all beings, prostrations before the image and saints, renunciation of earthly enjoyments and wealth, charity, austerities and vows, practice of Ahimsa, Satyam and Brahmacharya - all these will help you to develop Bhakti.