Are you afraid that your guest bedroom with twin beds might look a little young? There are ways around it — and you can have fun with color! Check out this sunny yellow room with white bedding from Carla Aston or go for blue with black bedding like this second example from HGTV.
If a chalkboard does not fit the sleek contemporary style of your bedroom or you feel that it is simply not what you are after then splurge on a gorgeous piece of artwork a painting or even a poster that has the same visual appeal of a chalkboard filled with handy artwork. There are many such pieces around that will both dazzle and delight you and add dramatic flair to the modern bedroom.
For a coastal beach theme you can really have fun with the decor. Go all out with sea-inspired wall art pieces of coral and shades of blue and other soft/neutral colors. Pottery Barn even has these lovely sheets to go along with your beach look.
For bedrooms that lack enough wall space a plain old bookshelf used as a headboard is one of the best ways to combine two pieces of furniture into one.