How can I update oak woodwork?

How about new wall decor? Choose a theme and run with it, I'm a big fan of nautical bathroom decor. Enjoy!

How about using a gel-stain in a darker wood color like walnut or redwood for your trim.

As to bathroom, maybe do a spa theme with cool pale green walls, then maybe try some of that patterned film you just wet and squeegee on to 2 sides of the mirror to reduce size, or frame whole mirror. I did 2 real high up windows in my bedroom that are like 5' long with a green leaf pattern film. Looks like trees now. https://www.amazon.com/gp/product/B00HJG363G/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1

They also make a great stain glass patterns.

Not hard to change out fixtures either. Just need a good pair of clamp lock pliers, teflon tape. where to turn off your water, and new fixtures. Check out youtube for videos.

Are you a renter ? is that why you can't paint woodwork. In your bathrooms why not put frames around the mirrors, I have same thing and I framed putting frame down center to make it look like 2 mirrors, you can take measurements and have your frame cut for you at the store. As for the décor go for what you like, look on line for ideals and adapt for your room. Try Habitat for Humanity for lights or closeout sales. For tub/shower & sink fixtures again please yourself, but do shop around. As for woodwork if you can't change try using a tinted paste wax to darken or lighten. Good luck

If you can't paint the woodwork in the room, I'd try to pull the eye away from that by introducing a high contrast look for the bathroom. By that, I'm referring to a dark color against a crisp white .... such as the ever-popular "nautical look" of navy and white! Perhaps, you could paint the walls a sharp navy and white stripe then introduce lots of fluffy white towels to keep the room as bright as possible. I'd remove any extra do-dads, knick-knacks, clutter, etc. then make a nautical themed wreath to hang on one wall. Perhaps a grapevine with natural color rope then about 3 seashells glued on (in a cluster) as trim then have an oblong basket on the toilet tank. It could hold extra bars of soap or something. The trick is to keep the room as pared down - but classy - as possible. If you dislike stripes, perhaps paint three walls a creamy white then one wall a rich navy. If you aren't the crafty type, forgo the wreath idea and hang one print on the wall above the toilet or if the print is on the small size, buy two and hang one above the other. If the room is rather dark, hanging an extra mirror (above the tub if there's no tile) can bounce the light around the room.

Here's a few nautical wreaths:

another one.

And here's the third, and last, wreath suggestion.

Thanks so much for all the good ideas....now to get to work:)

I took wainscoting painted flat side black and front side the color I wanted; cut ends at 45° angles and glued to edges of mirrors to frame them. Made all the difference in the world.