Buy Vogue, Tatler and ID for example.
Stick the campaign posters onto yourr wall, and print photos of you and friends all over.
Buy small sequins and paint and decorate walls.
If you do it in one room, only do it to one side of the wall.Too much will look tacky. One wall will make the guest who walks in immediately focus on the wall but not feel cramped.
dont ignore stores such as matalan, wilkinsons, and supermarkets. pictures, cushions,vases etc cost a fraction of the price. keep walls neutral. use a rug rather than replacing carpet, photos add a personal touch. most of all have around you what you like and what makes you happy, remember it is a home not a showroom.