Hey, Great piece overall ! I suggest you to place the cauldron in the middle, since your character is purely standing right to us. It makes the scene more naturals, or you could also choose to draw her more 3/4, because the cauldron is what she bewitches. Be free to add some other lights sources like candles/floating candles to play more with composition dynamics and having more fun ! No big lights here since the main light source is the potion she is concocting. Considere that if it's able to hard light the face, she would probably be blind by the light itself, and the lights would be more burnt on chest etc that are closest to the cauldron. don't light up the skirt, since the cauldron is not under it. I hope it's understandable since i'm kinda exhausted and my english is pretty bad ! Lovely day

Perhaps this could work? (The paintover)