Giving the children rewards, prizes, and allowing them to play video games as they wait is one way to teach them that coming to the dentist is a good thing.
Talk children through the procedures they're undergoing using kid-friendly language. In a routine cleaning, tell the child about the tooth mirror, and tell them how you count teeth the same way you count fingers. If a child has to have a cavity filled, talk about how 'sleepy jelly' and 'sleepy juice' will put the bugs to sleep, a 'tickle brush' will clean the bugs out of the teeth, and a filling will make the tooth all better.
It's also important to talk to the child's parents, especially if those parents are afraid of going to the dentist. Children take all their cues from their parents, so asking the parent to set a positive, happy tone about the dentist is key to keeping children from developing fears and phobias about the dentist. Consider coming up with a list of kid-friendly nicknames for your dental equipment and handing out pamphlets or sending out emails to parents who want to talk with their children about the dentist in kid-friendly ways.
And don't forget to make sure that your practice web site reflects your 'kid friendly' attitude as well. Even if your practice isn't 100% pediatric dentistry focused like this practice, letting parents know about the pediatric services you offer on your web page can help spread the word.