How exactly to dress a bed is often more of an after-thought for many people when renovating a bedroom. However, the bed really is the centerpiece of a bedroom and needs to be given careful thought and planning as much as any other part of the room.
You want to try and incorporate all of the other elements of the room into the bed in order to give it it's proper place. As with everything else, it's all about design elements and principles. The more design elements and principles you apply to your bed, the better it will look.
While there are no hard and fast rules, here are some tips:
1) Match, or strongly reference the bed-skirt to the window treatment:
Using this principle of repetition instantly pulls your bed in with the rest of your room.
2) Think of contrast when selecting your comforter and sheets:
Unless you are working with a monochromatic theme, you will generally want the colour of your comforter to contrast with your main wall colour. This will help your bed to stand out in the room. For example, if you've selected a very soft, pastel colour for your walls, choose a coordinated, but more saturated colour for your comforter. Next, you'll want to contrast your sheets to your comforter. For example, if your comforter is a dark saturated colour, choose a coordinated, light coloured sheet.
3) Select a footer blanket/throw:Placing a folded blanket or throw at the foot of the bed is an excellent way to bring symmetry to the length of the bed. It is also a great place to add texture which brings more variety and interest to your room. Generally, you will want your footer to contrast with your comforter.
4) Use the header pillows to bring in the rest of the room:
You want as many of the colours used in your room to be represented in your header pillows as possible. Generally you'll want to start with one to match the sheets placed at the bottom, or back of stack (this is typically the pillow which will actually be slept on). Then keeping contrast in mind, you'll want to layer: one pillow to reference the wall colour, possibly one to match comforter, one to reference the footer, and one to reference the bed-skirt and window treatment (typically the decorative pillow placed at the very front of the stack). This should bring everything together beautifully!