The art of mixing art

I adore mixing and matching art. It instantly makes a space that was once dull and mediocre come alive. One thing that I have always struggled with, however, is how to mix art so it still looks cohesive. Personally, I always stick to two frame colors, like black and white, so it pulls all of the art together as one. However, like in the last picture, that doesn't always have to be the case. Do you have any rules of thumb when hanging art?


1,3,4,5) via lonny mag 2) via plush palette 6) elle decor
7) decorpad