A green top and mini skirt can genuinely be assessed as a relationship between two pieces in this picture. Exposed space separates the shorter top from the skirt. Colour and pattern still visibly connect the areas. A brown shoulder bag and darker tall boots introduce further blocks. The raised arms influence the apparent waist gap, so include that posture in your interpretation.
For your own selection, lower your arms first, then try sitting and reaching. Decide whether you want the exposed middle or greater overlap. A longer top or different waistband height can create another transition. Compare the actual pieces together rather than treating the gap in a pose as a fixed garment property.
You do not need to copy every dark companion. Try bag or shoes as a connecting accent first and add the other afterwards. If you want the green areas more prominent, choose a quieter additional colour. Whether these pieces were sold as a set, and their fibre content, cannot be established from the photograph.