I was just talking with one of my personal clients about wearing brown & black together. I had been trying to convince her that it's a-ok and can look really chic but she was hesitant. I laid down outfits for her and took pictures so she could see: it really does work! Then just this past week she said to me: "Kara, I did it I wore brown & black together and it looked great!"
One way to ease into wearing brown & black together is to add a white or cream element to the outfit. An all neutral outfit always looks great.
When you're ready to jump in fully, stick with lighter shades of brown: cognac and caramel instead of chocolate or coffee.