Pick up some massage oil from your local bath and body shop for a nice, sexy, naked massage after a hard day. For a special treat, have your partner use it on you.
Buy new sheets for your bed. Try satin or another sexy color-fabric combination -- like red cotton sheets -- for a fresh feel in your old bed.
Make sure your undercarriage is groomed. Doesn't matter if you wax or shave, just make sure it's nice and neat for your sexy night.
Buy some new lingerie. Even discount stores like Target and Walmart sell it -- and sometimes it's even cute! Pick up a couple of pairs of new sexy undies and toss those huge granny panties back into your closet (or burn them, as the case may be).
Set up a nice romantic bath for the two of you. Turn out the lights, light some candles, pour some good-smelling bubble bath into the tub, and take a nice relaxing bath together.
Find some finger food and feed each other in the bedroom (I'm thinking strawberries or chocolate -- not pad Thai), or wherever you plan to get busy.
Send some racy texts to your partner throughout the day to get him in the mood.