It's very easy, inexpensive and has to be much better for the environment than all the sprays and bottles of yuck that you find at the supermarket.
Simply mix olive oil with your favourite essential oils and you are set. I use about 1/4 cup of olive oil and add the oil(s) until I am happy with the fragrance, usually just a few drops.
I make up a small amount when I need it and if I don't use it straight away it acts as a lovely room freshener when left on the kitchen bench. Now simply rub into your timber furniture and polish off for a lovely, scented sheen.
In the past I have used lavender oil for the bedroom furniture and lemon oil for the rest of the house, but I'm starting to experiment with different blends. My favourite at the moment is an equal amount of rosemary, peppermint and lime oils. Delicious!