Shastra has clearly laid down the definition of Bhakti. Bhakti is of nine types.
1 shravanam kirtanam vishnuh smaranam vandanam
archanam padasevanam dasyam sakhyam atmarpanam
shravanam - listening to shastras which tell the glory of the Lord from a relevant Guru.
kirtanam - chanting lord's name ,naming children by Lord's name.
vishnu's smaranam - remembering Lord in every aspects of Life.
vandanam - paying respects to images of Lord through namaskar. here animate inanimate things represent a particular image of God. knowing and behaving thus need knowledge.
archanam - Doing Pooja of Lords' vigraha in a vedic way as prescribed to pefection.
padasevanam - doing dhyana of lord's feet in the solar chakra or sahasrar.
dasyam - declaring oneself as servant/slave of God and acting thus as though completely serving him in every form HE exists befittingly as liked by HIM .(again point of thorough knowledge)
sakhyam - treating Lord as one our close associates like Friend, Brother,Father,Child,Lover etc.(Not all are eligible for this kind of devotion).
Atmarpanam - completely devoting oneself to the servitude of Lord , with even daily chores also to be taken care by Lord himself .Such should be the conviction that everything about self is giverned by Lord. it is upto him to look after you.(Again a case of extreme knowledge , not eligible for every one);
So it is clearly seen that devotion is a clear knowledgeable affair and not one of histrionics. You cannot neglect studies and say i am devoted and God will take care. You cannot say i am more devoted alhough less knowledgeable and hence i will not abide by learned.Knowledge increases devotion , devotion increases knowledge. Gnyanmay Bhakti (Devotion coupled with knowledge) is what appeals to GOD.
Say you love your Father. why ? if you say" i dont know, i just love him. " you are lying or you dont completely love your Father . But when you understand that your father had taken lots of pain in protecting you all through your childhood , in raisng you, in giving you education etc.Finally when you understand that he is chief instrument to have brought you into this world to carry forward your sadhana . Your love towards your Father increases manyfold. Your love (increased ) leads you to follow your Father in many more ways , with each success of Father you finally decide , i would become like my father ,then i cannot be as great as him . But definitely i shall emulate him to the extent He shall appreciate me.
Similarly when you are more knowledgeable about GOD you start loving him with devotion. When you listen to Bhagavat , you understan how lord protects his devotees through stories of Prahlad, dhruva, ajamidha,madhava,arjuna etc you develop faith in HIM. also your own experiences consolidate above faith. Finally you understand it is GOD alone who is pervading all over ,with entire universe at HIS command yet he exclusively takes vare about you . You lose interest in everything other than HIM . because every other thing is only because of HIM .You start seeing HIM everywhere in every being. (Aprokshagnyana). You yearn nothing but his presence and His grace, like a Father mad about bringing his wayward son into his FOLD , like a lovestruck man helplessly longing for a loving glance of a beloved,like a miser ever looking after his wealth ; One seeks GOD everywhere successfully traeting Gold and mortar equally , unaffected by sorrows and pleasure , heat and cold, onepointed towards LORD .Lord takes him to his abode granting him mukti of four types sayujya ,samipya ,salokya and sarupya in VAIKUNTHA.