Just a few ideas -

Pick two complementary colors to introduce. Nothing white, black, grey or beige. Use these in towels, glam-looking vanity stool, baskets, you could even do a feature wall behind vanity with stool with peel-and-stick wallpaper in a fun pattern. Rugs would work if the are none-slip. Add color to window covering. Decorate vanity with colorful jars with make up brushes and perfume bottles. The room lacks a uniqueness that color brings.

I would also limit the various bottles of shampoo, etc., in your shower niche. Those are not the ‘complementary colors’ you want as accents…at least not all together. Or, put them in matching/coordinating bottles. The current window treatments clash with the white/gray/black theme. Something colorful as Sharon mentioned above would be better. Or, change out your towels and rugs to match the window treatments. Bring home some hand towels of various colors to get ideas—you can always return them, it’s an inexpensive way to see what works.
I just remodeled a bathroom with grey-veined floor and wall tiles; white trim. I’m using pale silver/grey towels & rug and teal accents and I love it!

Thank you! I’m not great with colors. Which go best with gray and whites?

Looks to blues and greens in the artwork. On the "cooler" end of the spectrum.

What is on the left out of view? Does the vanity table have to live in this room, or could you relocate it? If it has to be there, perhaps look for a small demilune table or desk that could be repurposed, and possibly painted an accent color. Not a pro, but I'd suggest sticking with solid accents and fabric shades since you already have 4 different patterns between the shower wall and floor, counter and floor tile. I agree that bringing home towels is a great way to try a lot of different color combinations easily. Gray looks good with so many colors....

IMO the make upvanity needs proper lighting and you have no where to put it I aslo hink you used nice materials and cheaped out on the medicine cabinet I would remove the make up vanity and put it in a space where you can get proper lighting I think too many finiahes already but I would remove the sconces and get a larger medicing cabinet or better yet a new mirror and forget the medicine cabinet but regardless those sconces need to move and th emirror needs to be much bigger and IMO a nice light ba LED 4000K above the new mirror would be better . As for color I like blues and greens and a nice simple white shade with a faux roman shade in a simple fabric in either of those colors along with towels and accessories IMO no more gray. No wood shades either

I love what you have done so far. As the other posters have said, you do need to change the window coverings. I am just finishing the remodel of my master bath which has a gray floor, white subway tile shower and a white vanity with a Carrera marble top. I am painting the walls a very pale green and bought green towels. I have glass tile in green shades in my shower niche and as the backsplash for the vanity. Even though you don't have any green anywhere else you could still use it for your accent color. The teal mentioned earlier would also work. Actually, almost any color would work as an accent with what you have already (except for tan, brown,

beige or rust). The trick is to get the right shade - so as the other poster said, bring home some hand towels to try different colors. What's your favorite color?

Add pretty towels and matching washable bathroom rugs. You can buy three sets….aqua, lavender, and gray or green. No demo or big expense!
The grass cloth shade on the window looks “off”, so I would replace it with a gray or a white shade.
You can make a skirt for the makeup table and attach it with stick-on Velcro tabs.

We might recommend trying some colorful towels, a few plants, and perhaps some artwork with a little color as well. You could even replace the rugs in a deep blue color to bring in more color. Below are just a few bathroom designs of ours that might help you with this specific dilemma.

Master Suite · More Info

Showcase House 2014 · More Info

Transitional Home · More Info

The medicine cabinet, designed to be recessed between studs, sticking out is very awkward. Try a pretty large flat against the wall mirror before changing lights. Floor tile is very pretty. I think it is the very flat gray walls that are “off.” Is there a non gray shade in the floor tile could use? Otherwise pale blues or greens as others suggest as well as colorful towels and rug. The make up table is trying to be the “same” as the vanities. It does not work. Someone posted about a colorful non matchy make up table, add in cute bench, and see if works. From pics cannot tell if trying to squeeze into the space. If so, then eliminate. Your critical finishes and expensive stuff are beautiful just needs some tweaking.

Thanks @husterd what sort of metal should the mirror be? The walls are actually BM “simply white” so it may just be the lightning.
What material vanity should it be? Dark or medium wood? Black?

Sorry, on my iPad the walls looked gray. Your fixtures, faucet, shower pieces are either chrome or nickel, the drawer pulls gold or brass, hard for me to tell. You have mixed metals. Either one unless you like to keep the mirror the same metal surround as the sconces. The dressing table is harder. I lean to a color, black is a color. Really need to see pic of the area table is in. Is your style traditional, modern or a bit of glamour? Or a piece that resembles/ties in with the style of your vanities. Should have some drawers. An item probably have to search for and know it when you see it. I am assuming you like to sit when putting on makeup.

If lucky a mirror with both metals,

Don't change the vanity unless you need to - from here, it seems to highlight the 'movement' in the counter. Warm handles nice too... ??

W 5" / D 6" / H 9.75"

Renwil Steel And Glass Barrette Wall Sconce With Satin Brass Finish WS020 · More Info

If you keep the shades, and mirror in warm tone, you could try a similar 'warm' like these-

Classic Plush and Absorbent Turkish Cotton 6-Piece Towel Set, Hazelnut · More Info

Or just say you like a minimal watercolory image - might fit with bare-looking shades -

"For Free" by Andreas Lie, 26x18x0.75" · More Info

"Element" by Andreas Lie, 26x18x.75 · More Info

Designart Running Water Ii Traditional Framed Canvas Art, Gold, 16x32 · More Info

Clifton 1-Light Wall Sconce, Warm Brass · More Info

Something rough, imperfect could add-- W 26.75" / H 34.5" blue green finish and deeper undertones give the mirror depth

Zinc Decor Elwood Distressed Wood Wall Mirror · More Info

Palmer Wood Octagon Wall Mirror, Blue 28x36 · More Info

The 36" might cover the 2 'emptied' electrical -

Orbit Round LED Mirror, 30"x1.75" · More Info

Is your home vintage knobs and such? maybe this would tie in with hall flooring, etc...

Hutton Round Wood Wall Mirror, Rustic Brown 36 Diameter · More Info

Your color choices suggest that you want a calm, serene space, but you have an awful lot going on here, and it's fighting that idea. Suggestions:

- Everything is kinda in the same color scheme ... pick ONE bright friendly color for towels. Blues and greens are naturals in bathrooms, but you could also go with a bright coral or a pink, if that suits your taste. But no neutrals ... you need a star in this room.

- Lose the baskets under the vanity /replace with those pretty folded towels; if you need-need those baskets for storage, you could go with two towel stacks and a narrow basket in the middle ... but the towels in this space will bring in some color AND remove the baskets, which are looking cluttery in an already-busy space.

- I'd keep the gray floor mat you already have. Those towels under the vanity will bring in a lot of color near the floor, and you don't want to over-do.

- Add one large colorful piece of artwork above the toilet ... tie into that towel color.

- Remove the shades; the warm color isn't good with your cool grays. Instead, choose pretty print curtains to coordinate with your new towel color. You have great light in this room, so choose light, breezy curtains that'll give you privacy while allowing some light to shine through.

- Is one of those windows larger than the other, or is that a trick of the photography? If they are different sizes, mask this by hanging the curtain rods at the same height.

- The medicine cabinet is just bad. Its on-the-wall (instead of between the studs) mounting makes it clunky, and together with the two lights make the wall look choppy and cluttery, and they're right there in the middle of the room ... I think they are the heart of the problem. A larger mirror in a simple rectangular shape -- a framed mirror -- will make this space look calmer, more put together. The vanity, with its bright hardware and shelf underneath is rather "busy" ... you can't afford busy up top AND busy down below.

- Yes, the shampoo bottles in the shower are looking cluttery. Thing is, all these magazine pictures show us these all-glass showers EMPTY, and they look great ... but you have a real person shower that actually gets used, and you use toiletries. You could decant your products into pretty, colorful bottles ... but that's an ongoing chore, and this is not a make-or-break.

- You have a lot of junky-junk at the sink, especially the plug-in-toothbrush. With some organization, can some of this go into the drawers?

- Similarly, the make-up vanity is cluttery. Perhaps a couple baskets could "contain" some of these things? Could you trade that plain make-up mirror for something with a pretty frame? Gold to tie into your vanity hardware. A small flower vase would elevate the make-up vanity.

- Finally, how about some greenery on the toilet top ... or perhaps hanging in front of the two windows?

There's a second sink/vanity in the space out of the pictures. What is that mirror/sconces like? Is this a main bath or ensuite? Hoping it is a private space. Mrs. Pete hit the nail on the head--this is a WORKING room and with that comes the things of life. You can either spend a lot of time hiding reality or just look past it knowing it's not a public space and get over all the foo foo fancy bottles/baskets that make work!! Colorful towels/new curtain will bring your vision home. The mirror is a thing one sees- medicine cabinets not recessed. I got over being bothered decades ago but I have to agree the cabinet and the sconces isn't helping you. Why do you want to get rid of the make up table?? What's not working for you?? Personally make up/hair in a moist bathroom is counter indicated so mine would never be in that room but it appears you have SPACE.

Ditch the medicine cabinet and use framed mirror (s). I agree with comments on window treatments and bringing colors in with towels and paint.