So what should you do? How should you practice?

First, thoroughly learn the tune. Know the melody and chord changes cold. transpose it and play play through it in every key Harmonize the melody so the melody note is the highest pitch in each voicing you play. For the sake of study, harmonize every single note. You may musically decide later that this is not needed. If possible, (because of range considerations), learn alternate voicings for each melody note- different string sets and/or different pitch selections.