Simply by decluttering you can make a small space appear larger.
White or very pale neutral colours make an area appear more spacious, the walls appear to recede.
Single colour paint schemes increase your perception of space, causing your eye to easily move around the room, lessening your ability to perceive dimension.
The use of glossy surfaces will reflect light around a space. Consider a large mirror to increase the perception of size. Dark glossy surfaces and glass-top tables also reflect light and create a greater sense of space.
Consider using small-scale and light-weight furniture such as armless chairs. Multi-functional pieces such as a nest of tables are ideal.
Good storage options are useful. Consider a built-in-bookshelf or bedhead.
Using Roman or Venetian blinds as window treatments will provide a less cluttered look.