I would say to take down the wallpaper and repaint with something light. Also a new shower curtain and window shade. Perhaps a lighter green, or a blue. Depending on how budget this is, I'd also say to change out the faucets to something without the big acrylic handles.

Yes! Taking down the wallpaper has been the issue. It is such a pain. I do plan on taking down the mirror. On the far wall around the window, I had considered placing stacked tile… Like a faux feature wall. This would be pricey I realize but then all the other walls could be painted a lighter color. I like the sconce idea. I do need new countertops and sinks and faucets. I may do this in stages.

I would definitely take down the wallpaper and paint a nice light paint to make the room look more spacious. Also I would replace the mirror. We took our big mirror down and replaced it with 2 framed mirrors that I found very cheap at Kirklands, also HomeGoods is another place for cheap mirrors. Then do individual lights over the mirrors. I would also chance out the towel bar and toilet paper holder with updated nickel finish ones. Then getting a lighter colored shower curtain to keep it bright. If you really want to brighten it up you could revamp your vanity by painting it.

The easiest and least expensive things would be...remove wallpaper and then paint, remove the shade, replace the shower curtain, replace the light fixture. Those things will be HUGE improvements. Natural light is free.

Paint, mirrors, fixtures

If you want to keep that large mirror - you could frame it out with trim and paint it

Wallpaper, light fixture over the vanity, and towel bar. New mirrors would be nice too. And you can get them around $50 a piece on Amazon.

This looks like a fun project. If stacked tiles sounds too pricey you might consider a metal wainscot. traditionally people have used corrugated, but I think a flat rolled or Ultra Batten panel with some texture, like our Rawhide, might give you a unique modern feel without a lot of cost. Good luck.