Krishna says, "Those who fix their minds on Me, worship ME (in the manifested Form) endowed with 𝙎𝙝𝙧𝙖𝙙𝙙𝙝𝙖 (trust), I consider them to be the best in yoga" (12.2). Though this answer is specific to Arjun, it broadly applies to all of us. Secondly, 𝙎𝙝𝙧𝙖𝙙𝙙𝙝𝙖 is the foundation for any spiritual journey.
Krishna immediately clarifies that the path of the Formless or Unmanifest is also a path to reach him. He says, "But those who worship the Formless aspect of the Imperishable, the Indescribable, the Unmanifest, the All-pervading, the Incomprehensible, the Unchanging, the Eternal, and the Immutable; by restraining their senses and possess even mindedness in every circumstance, such persons, rejoicing in the welfare of all beings, also attain Me" (12.3-12.4).
He compares both paths and says, "For those whose minds are attached to the Unmanifest, the path of realization is full of difficulties. Worship of the Unmanifest is exceedingly difficult for embodied beings" (12.5).
Any journey starts from our current position. A journey to Delhi from Chandigarh would be in one direction and the same from Agra would be in the opposite direction. Similarly, our journey to 𝙋𝙖𝙧𝙖𝙢𝙖𝙩𝙢𝙖 depends on our current position.
Broadly, our present condition is that we are in the midst of attachment (includes hatred) to things, people, feelings, memories and belief systems. This leads to multiple minds, often contradicting each other (polypsychic) -one for each attachment. The journey is from multiple minds (attachments) to one attachment to the 𝙋𝙖𝙧𝙖𝙢𝙖𝙩𝙢𝙖 in the Form (manifested). Finally, even this attachment gets dropped to be one with 𝙋𝙖𝙧𝙖𝙢𝙖𝙩𝙢𝙖 .
This background helps us understand 'fixing the mind on Krishna' (12.2) as having one pointed mind towards 𝙋𝙖𝙧𝙖𝙢𝙖𝙩𝙢𝙖 from multiple attachments. While advising the path of Form (manifested), Krishna understands our difficulties with attachment and hence, guides us to fix the mind towards him with 𝙎𝙝𝙧𝙖𝙙𝙙𝙝𝙖 .