The problem with designing a white bedroom is you may not know when to stop. First decide how much white you want to give your bedroom. There are white room enthusiasts where all the design elements are white and there is very little actual colour. Take this route if you like austere surroundings. However, people who like more warmth and colour can design a bedroom with a predominance of white colourful accents.
You can paint the walls and ceiling white. White goes with any colour so contrast the surfaces with wooden cabinetry of another favourite colour. You may not want a white bed but you can pick colourful bed sheets and pillows with a white background. You may do well to have a white table and chair and plant a colourful lamp on top of it. Your book shelf can also be white since the books will all be of different colours.
You can also have a white room with coloured walls, but choose a colour that white can contrast appealingly, like shades of blue or green. Here, your closets, cupboards and dressing table can be white. You could even install a white four-poster bed with a bed sheets and pillows that feature white. You may not want white or wooden flooring in this setting. So go with colourful tiles with a white background.
If you do want white walls, create an accent wall of a different colour. Set a white table and chair against it with some wall hangings. Install polished wood cabinetry, including the dressing table. Go with a wooden bed with all white bedding. Let the flooring match the colour of the accent wall and set it off against an all white rug or one that has a predominance of white. The trick is to design a white room and still give it colour.