"The resolute determination of Self-realization is not formed in the minds of those who are attached to pleasure and power, and whose judgment is obscured by ritualistic activities. (2.44) Become free from pairs of opposites, be ever balanced and unconcerned with the thought of acquisition and preservation. Rise above the three modes of Material Nature (goodness, passion and ignorance) and be Self-conscious, O Arjuna. (2.45) To a God-realized person scripture is as useless as a river in a flooded area. Scripture is only an aid to God-realization, not needed after one has realized God." (2.46)
"I personally take care of both spiritual and material welfare of those ever-steadfast devotees who always remember and adore Me with single-minded contemplation. (9.22) O Arjuna, even those devotees who worship the deities with faith, they also really worship Me. (9.23) Whosoever offers Me a leaf, a flower, fruit, or water with devotion; I accept and eat the offering of devotion by the pure-hearted. (9.26) O Arjuna, whatever you do, eat, give, or sacrifice, do it as an offering to Me." (9.27) A dedicated heart full of devotion is needed to obtain God's grace, not rituals.
"O Arjuna, neither by study of scriptures, nor by austerity, nor by charity, nor by ritual, can I be seen in the form as you have seen Me. (11.53) However, through single minded devotion I can be seen in this form, can be known in essence, and also can be reached. (11.54) One who does his worldly duty for Me, to whom I am the supreme goal, who is my devotee, free from attachment and without enmity towards living beings, realizes Me." (11.55)
"Transcendental knowledge of the scriptures is better than mere ritualistic practice; meditation is better than scriptural knowledge; renunciation of selfish attachment to the fruit of work is better than meditation; peace immediately follows renunciation of selfish motives." (12.12)
The closest Krishna comes to prescribing ritual seems to be in the event that an individual is having a hard time focusing on Him:
"Therefore, focus your mind on Me, and let your intellect dwell upon Me alone through meditation and contemplation. Thereafter you shall certainly attain Me. (12.08) If you are unable to focus your mind steadily on Me, then long to attain Me by practice of any spiritual discipline; such as a ritual, or deity worship that suits you. (12.09) If you are unable even to do any spiritual discipline, then be intent on performing your duty just for Me. You shall attain perfection by doing your prescribed duty for Me --- without (selfish) attachment --- just as an instrument to serve and please Me. (12.10) If you are unable to do your duty for Me, then just surrender unto My will; renounce the attachment to, and the anxiety for, fruit of all work by learning to accept all results as God's grace, with equanimity." (12.11)