Treat each note in your chord as a separate 'voice' (like singers in a choir). When the chord changes, each voice should move to the closest note in the next chord — by 0, 1, or 2 frets.

Three rules

• Keep common tones (notes shared between both chords) on the same string
• Move other voices by the smallest step possible
• Avoid parallel motion in perfect 5ths or octaves (sounds hollow and amateur)

Through ii-V-I

Dm7 (F-A-C-E) → G7 (F-B-D-G): the F stays, A drops to G, C drops to B, E drops to D. → Cmaj7 (E-G-B-D): F→E, B stays, D drops to B? Adjust voicings until each voice moves at most a step. That's good voice leading.