Choose furniture that is easily put to one side when they are not in use or go for furniture that follows the rhythm of the day. You might need a desk for the day, but a dining table for the evening.
A few style tips can also make a room seem bigger. Stick with the same color scheme and use tone-in-tone colors. This will create a calm, coherent look. Glass, white or shiny surfaces will bounce the light around leaving you with a sense of space. And most importantly, have plenty of storage to help you keep it tidy.