Certain tips that I find helpful are
don't buy it unless you really need it
I totally agree Angie. My home is decorated in the 'minimalist' style with a definate country style, as we live in the country. But I do find it is a constant battle to keep the clutter at bay.
I told hubby some years ago - "No more stuff". It had gotten to the point where I had to clean out old 'stuff' to make room for the new 'stuff'. I love to cook, and was more than happy with my kitchen appliances, and certainly didn't want anymore. Hubby also admitted that he felt the same with all his tools.
So our new philisophy is to ask ourselves before buying anything is "Do I really need it, or will it just become a dust collector?" We usually give each other money for gifts, and spend it on home improvements, instead of 'stuff'. The only exception being books and cd's, as we have a large bookcase.