Apart from all the decor alternatives offered by retailers, nature has a bounty of colours, materials and shapes which, if used creatively, can give character to a space. One very popular and never-out-of-fashion item is sea-shells. They can be used across a home to lend an earthy and cool feel : be it as space separators (with the help of shell curtains) or made into wall hangings or picture frames. Alternatively simply keeping a bowl of an assorted collection of sea shells on the living room centre table can be a conversation starter. Stones can be similarly used.
Pulses and grains of various colours can be used creatively too. The best part of most natural items is that they are mostly perishable and gives you a good reason to change the decor often and keep a space looking fresh and interesting.
Besides the usual greens in pots and plants which are used indoors, a bunch of fresh flowers or even fresh fruits and vegetable can be effective as decor.