The ideal way to give flair and impact to a small room is to apply color correctly and use a decor theme. Light colors are better for a small space since they will make the room seem larger. Not only that, they immediately give character to a room. This will also counteract its smallness. By giving a small room a special theme and sustaining it throughout the total look, you will also add interest and quality.
For example, you could use a maritime theme. In this case, light shades of blue or sandy beige hues for the walls would be ideal. There are various ways of applying the maritime theme. The one could be a romantic approach. Another possibility would be to go for a modern, crisp look.
For a romantic bedroom, you could imagine a mahogany cabin on an old boat of the 19th century. The bed linen would be white and beautifully embroidered. You could add small-sized pieces of furniture with a rich mahogany finish. These would look superb set against a blue background. Pictures of the ocean showing sunsets with a glowing orange and dark blues would round-up this theme. Pictures of shells, seagulls, dolphins and colored fish could also add an attractive character.
The other possibility for applying the maritime theme is to go for a brisk, modern look. You could paint the walls in a very pale blue shade. The bed linen would look vigorous and brisk if designed in blue and white stripes. Lamps could be in a clear metal with white shades. Pictures of boat themes, either modern photography of streamlined yachts, or geometrical interpretations of boats, would be ideal for creating the joy and vigor associated with sailing and the ocean.
By adding colors and adapting these to a special theme, you can always make small bedrooms look very special. Your tiny guest room will no longer be the most boring space in the house. On the contrary, you will have transformed a small non-descriptive room into an expressive, stylish and charming bedroom.