What a fun question! This summer I was teaching summer school and another teacher came in one day wearing her LBD and it stopped me in my tracks! She had combined it with brown and it was fabulous and casual. She was wearing a wide brown leather belt, brown sandles and brown wood jewelry. How about black tights, brown boots, and some very casual brown/burnished gold accessories? Black and brown together is oh so chic! A scarf with browns would work too. If it's cooler you could wear a black cardigan and put a brown belt over it. I'm not a denim jacket kind of girl either :) I just purchased a 'vegan leather' motorcycle jacket and that would be casual and a little bit tough over a LBD! Have fun, use what you do have and express yourself!