When shopping for furniture think about the space it will occupy - a nest of tables is compact, as is a gateleg table which folds away. Folding or stacking dining chairs may be useful buys - you can even hang some furniture on the wall to store it efficiently. Try to choose items which can have a dual life - a chest can be used for storage and as a coffee table. An unused alcove on either side of a chimney breast can be turned into a small desk area, ideal for a computer or hobby table - with plenty of space above for bookshelves. In the bathroom, a shower takes up less space than a bath and swapping the two will create more room.
Mirrors can play a vital part in creating the impression of extra space.
Install a big mirror and the room will immediately seem a lot bigger. The mirror trick will also work in dark and cramped halls and stairs and help produce the appearance of more space and light. Make sure every inch inside wardrobes is well used, with racks and shelves crammed full. And do not forget the space under the bed - you could store loads under a bedstead. Finally, take a look at the cupboard under the stairs - one of the most unlikely areas for generating space.