6. Put basic terra-cotta pots to work on your mantel. Simple terra-cotta pots can be found at most big garden and craft stores for a song — or maybe you already have some gathering dust in a cupboard somewhere. Choose a variety of sizes, from tiny to medium, and fill the pots with shade-loving houseplants (like ferns) from the nursery. Place them in a cluster on your mantel, propping up one or two with a book or an upturned bowl to give some height. Remember, when using old pots, be sure to scrub them thoroughly first.