This is what our second bathroom looked like before I painted to update it a bit. As with most of my "renovations"... everything had to stay the same (the slate, sink, vanity, taps etc) and so I had to just work with what was there.
There was certainly an abundance of slate, and it sits halfway up the wall which makes it hard to hang pictures to cover it so that it's a bit more balanced... but I got a selection of my child's paintings (plus one of mine - the black and white one), and stuck them up with blu-tac over the wall and the slate.
Then I added some lettering (also stuck on with blu-tac), a starfish, a mirror that I purchased half-price from Target and painted white, and all the other bits and pieces that need to go into a bathroom for everyday use! On the ground next to the bathtub is the top of an old broken shoe rack from IKEA that I had... it looks great as a wooden bath mat!
And this is how it looks now!