Its a really lovely room! what a great place for kids to share. I like kids sharing rooms. I think you need another colour to tie it together. I would suggest a blue tone.... teal, navy blue, duck egg blue. to tie it together. Its a little to pale and looks sparse, but actually isn't. I would leave everything exactly as is, BUT, paint the back wall behind the bed teal and find a simple navy blue wall decal that is fun and kid- like maybe one with a sillouette of a boy and girl playing. I would paint the wall behind the sofa duck egg blue. Then I think it would suit both kids more and look more kid friendly. the blues will balance the pink and cream, but because you have a pale carpet i don't think it will look too dark. don't worry about making it totally kid like, its a room they will grow with, not a kindergarten, and it also needs to peaceful and restful for sleeping. besides with their art on the walls and bright toys everywhere it soon looks bright and kid like. Good luck!

Paint the wall behind the bed the purple I have shared. Paint the headboard and door the gold from bedspread, white or grey. Pick up two standard pillows too to add to bed. Add a purple shag rug. Hunt the Internet for abstract glass decals to adhere to walls over bed. Your photo collage should go on another wall- over bureau perhaps - as it is currently hung to high. Putting it over the bed also makes it hard to see photos, which is the whole point. Check out IKEA for fun, inexpensive bedside tables ( not that color).

Not sure if you need curtains when you have wallpaper? It's already a fairly busy room and it may make it feel smaller and heavier, but if you want curtains I would duplicate the same color as your bedspread.

I would use the greens from your bedspread. Since you have green in the bedspread, and brown and white tiles, those 3 colors need to be your focal point. So I have painted your wall a bright olive green ( the darker color in your bed spread) and the ceiling either a brown to match the tile or a white to match the rest of your ceiling. then or I think this last one is a little tamer . But you should be able to paint over the tile. WHAT kind of tile is it? If it is ceramic you can paint it. Here is a link about how to do it: https://www.sherwin-williams.com/property-facility-managers/education/styles-and-techniques/sw-article-pro-resuscitateold.html