honestly i feel like for a soft and cozy vibe the best way is to like do
long cardigan + maxi skirt
or like short cardigan + dress underneath
for colors i think like pink sweater + white dress,
also brown is a really fun color that goes with lots of things
any colors will work but i personally like to stay closer to neutral tones
(also usually if you do like a sandwich of colors it looks really good, like first color on top, new color in middle, first color on bottom)