Where to capo for G minor
Put the capo at fret 3 and play G minor using E minor shapes. That is the easiest of the eight positions ranked below, and it is what most players reach for. Against playing G minor open, it drops the mean difficulty of the key's seven chords from 5.6 to 3.4 and gains 13 ringing open strings.
You want G. Capo 3 and play in E.
All eight positions, ranked
Each row transposes G minor down by that many frets to find the shapes your hand would actually make, then scores the best voicing of all seven chords — fewer fingers, less stretch, closer to the nut, fewer muted strings. Lower is easier. Standard tuning (E2 A2 D3 G3 B3 E4).
What you are playing
The seven chords of G minor are Gm, Adim, Bb, Cm, Dm, Eb, F — the ones the ranking above is scored against. Their diagrams are on the G minor key page.