The final objective of GV is to obtain love of God. Bhakti or devotion is its expression and means at the same time. If one has other motives to perform bhakti, such devotion is not pure whereas if one's goal is just to please and love God such devotion is supreme and uncontaminated by material modes (in sanskrit called uttama bhakti).
Rupa Gosvami in his Bhakti-rasamrta-sindhu (1.1.11) defines uttama bhakti as the desire to please Krsna with no hidden agenda, devoid even of tendency to desire anything else than Krsna's happiness, with all one's activities being centered around Him (ānukulyena kṛṣṇānuśīlanam).
Supreme devotion is thus not limited to doing puja, japa and kirtan, as it is commonly believed. Among the nine limbs of bhakti (listed in SB 7.5.23) ātma-nivedanam is the most important one and all other limbs are just its parts. In other words, if you are not surrendered, then just chanting the name or doing kirtan is not supreme devotion while if you are surrendered then everything you do is devotion, such as going to shop, taking care of your parents, earning money in your job, and not just kirtan, japa etc.
See how well this ties with Rupa Goswami's definition and how it enables you to apply bhakti in your life. After all, bhakti is for everybody, not only for renunciates, which is shown by the example of gopis, Pandavas, Vidura etc – with all their duties they didn't have much time to do smaranam or japa, but in spite of that they are considered topmost devotees and models for us.
The idea that bhakti means all one's activities for Krsna also eliminates another popular notion: that the essence of bhakti sadhana is to meditate on a young gopi and her intimate service to Radha and Krsna (also known as manjari bhava).
Although this smaranam does exist its focus should not be so much on her body as on her bhava (consciousness). Being the highest manifestation of serving mood where all one's intentions, activities and thoughts are focused on giving pleasure to the beloved person (Krsna/guru), and where one's happiness depends solely on the happiness of the beloved, this is yet another confirmation of Rupa Goswami's definition and has nothing to do with the nourishment of sensual samskaras that such “sadhana” done by immature minds inevitably boils down to. Bhakti is never confined to one activity (smaranam in this case), rather it pervades one's whole life.
Now, the question remains how this devotion and surrender can be achieved.