Also, give them to teachers, leave them at the doctor's office, the library, the video store, anywhere there might be kids. After going on a field trip, send pictures and a thank you note, and of course your contact information. Most places will hang these up for the public to see. Make t-shirts and sweatshirts with your logo and name on them. Have all the kids where them when you go on a field trip.
People are sure to notice.
Offer three mornings of free daycare at a silent auction. Contact your local hospital. Most hospitals send out some sort of a welcome package to all the new babies. Ask if you can put a flyer or business card in it. As with business cards, have some inexpensive pens made with your daycare name and number.