In my opinion, a nice polished pair of brown dress shoes, whether you go with loafers, Derby shoes, or Oxfords, always look excellent next to charcoal grey pants
Tip : look for a brown boot with rich, caramel and cognac tones, not too dark, so you can easily see the color contrast
And if you're looking for some Fall inspiration, be sure to check out the new South Moon Under lookbook (which is SO dreamy!) Wearing Black Maxi Dress from South Moon Under c/o, Aritzia tee (similar), Miu Miu sunnies from Ditto, bandana, gold socks (similar), Maumero sandals, Chanel bag via Bag, Borrow or Steal (complimentary rental), Urban Outfitters belt, Like Gloss by Kylie.
What about skinny jeans