Krishna explains the method. Through consistent practice, with a mind that does not wander elsewhere, one who meditates ceaselessly on the Supreme reaches that divine being.
The word "abhyasa" — practice — carries real weight here. A child who writes the alphabet every day gradually develops beautiful handwriting. In the same way, daily remembrance of God slowly steadies the mind. It does not happen in a day, but it does happen.
"Nanyagamina" — the mind does not stray. This is difficult, but not impossible. A river finds its course over time, flowing steadily in one direction. With patient practice, the mind too learns to flow toward God without wandering.