Just like in fashion, rules of design come and go. Here's a cheat sheet to what can and should be broken for a modernized look to even the most traditional homes.
1. Don't Mix Metals
Eeek . . . this is a common misunderstanding. My rule is always to view metals in a room as you would jewelry. You would never think NOT to wear a gold bracelet if your watch metal was silver, would you? (That is an honest question - - I have a leather Cape Cod watch and always wear it with gold bangles . . . hopefully I'm not missing the boat on this one!) Okay but let's think bigger picture . . . brass and chrome look great together in the room as long as there are multiple of each object. For example, if your sconces were brass and you had a chrome bar cart things may look a little Wacky Wednesday (mom joke - sorry). But if you had 3 things that were chrome-toned - say your bar cart, a decorative bowl and a picture frame - your mixing would look intentional and fabulous.
2. Don't Mix Wood Tones
Eeek . . . I was at a furniture store once and the salesperson asked me if I wanted different legs to go on a sofa to match the coffee table. Um no thanks. Elements in your room should speak to one another not match. Think of those My Bob's commercials where you can get a 7-piece set of everything you need for a living room. That matches. But for your house, you want to layer and different shades of wood add interest and give a curated feel.
Why this works . . . the spindle chair's mahogany back, arms and legs breaks up the beige. At the same time, the light server behind the couch compliments the mirrors and doesn't allow that wall to feel too dark.
3. Don't leave a wall blank
Eeek . . . . not always. A fundamental principle of design is object/void (in architecture school I wrote a 30 page paper all about that . . . a real page turner let me tell you). You need void to allow the object (say a painting on another wall) to shine. Void also allows the eye to rest, which is important for a room not to feel to busy or cluttered. It is interesting to look at large gallery wall . . . ever notice how some of them feature large mats? This allows the wall to have multiple focal points while giving enough void for the eye to rest. For home design, if you have a statement piece on one wall, feel free to let that shine.
Why this works: There is a lot going on in this space. . . just look at the back wall . . a dresser, oversized art and a large window (perhaps a door?). However, it all works because of the wall behind the bed. Even more so actually because is is painted black - by allowing that large space to essentially disappear, the busy wall becomes a focal point that is not disrupted. Spoiler alert: I will do a post on black ceilings too. . . I would LOVE LOVE LOVE one in my kitchen but my traditionalist husband says no :(