most of the storage solutions we found are listed above, but a couple that worked for us that haven't been mentioned are:
*buy a small bin that you can put under the sink, there are ones that attache to the door, so your floor now won't look cluttered.
*radiator covers in hallway / smaller rooms, you've 'lost' the space anyway, so by putting up a rad cover you can gain a shelving area, handy for keeping small items on (when you come to sell, ditch the usual stuff of post, keys, take away menus and leave out nice flowers and ornaments instead
)
*keep non season stuff in your suitcases, in winter all your swimwear, flipflops, etc, in summer all your jumpers... and then store under the bed.
* look into putting 1 layer of shelves about 8-10 inches from ceiling in hall area, so you're books are out of sight... you can also look at putting small lights under the shelving units so it doesn't darken the hall too much.
* a friend had a large piece of canvas / clothe on her kitchen wall that she pins all her postcards, birthday cards to... it saves you cluttering your counter tops and is an ever changing piece of 'art' on her wall!
*another friend uses a chest as her coffee table, inside she has a small vacuum cleaner, and all her cleaning products... saving space in other areas.
*if you are still in the process of buying furniture, take the time out to measure out your rooms, and then measure our each piece of furniture you are considering. if you create a floor plan (the old squared maths copies are handy and cheap), then cut out what you're considering, and see what position is the best - don't always copy what was done in show house...
*consider putting in a breakfast bar... would putting you in free up another few feet for your living area.
*mirrors, put them everywhere! With light colours and lots of light being reflected around it can make the space seem bigger
*find ways of hiding your stuff, open racking / hanging in kitcher / bathroom can make the space seem cluttered.
Good luck.