My first apartment in Chicago was a studio and I absolutely adored it...even the fact that my closet became the perfect cozy bedroom. Ever since I have had a soft spot for small bedrooms. If you are lucky enough have one there are a few simple and basic tricks to make them functional and lovable. First and foremost do not ignore it just because it is small---don't be scared to invest in a lovely headboard fabric or dreamy curtains...
As in all rooms of the house--take advantage of the magic of mirrors!
Utilize all the surfaces you have--if you have a window sill maybe skip the bedside table. And consider lighting options beyond the traditional table lamp.
Go vertical with shelving and storage. And think of pieces such as bedside tables for other uses, such as a workspace or vanity.