Place a FOR RENT sign on your front doorstep with no information on the unit itself; just list your phone number. Your time is precious so don't waste it by spending 15 seconds writing how many beds/baths come with the unit, what the amenities are, how much it's going for or when it's available.
Seriously - I'm apartment-hunting right now and this is my new pet peeve. Why, oh why, would you only list your phone number on a FOR RENT sign?!?! I don't care if it looks like the white space was only designed to write in a phone number - give me some details!