Some rules when you are arranging shelves Put taller items in the back and group items in 3's. Odd numbers are better than even number of things. Try and make your arrangements in the shape of pyramids.
Even something as simple as a new shower curtain can really brighten up the bathroom.
Pictures of course can brighten up kitchen bathroom and living room...
From modern to traditional we have a picture you could use in your home on pine cat15 on Zazzle.com
Also wanted to mention you can mix prints you just have to stay in the same color family. You probably always wondered how the magazines did this with prints and it looks so good.. You can also go to neutral colors like grey and add oranges and even yellow items with it and look great.
I have picked up quite a few bits of information from the many furniture and decorating stores I have managed and worked in..
Good luck and Happy spring , Nora