1. Keep your window-to-wall ratio high.
2. Install floor to ceiling bookshelves.
3. Use semi-opaque materials to allow light into windowless rooms.
4. Create outdoor living space to add the feeling of square footage without the cost.
5. Opt for fewer walls, more multipurpose rooms.
6. Add a loft over your kitchen.
7. Actually, add a loft anywhere.
Sleeping and reading nooks maximize your space and provide privacy in shared areas. Snag space above your kitchen, bathroom, living room — there's no end to those versatile vertical spaces.