How do I get Daisy to stop barking when anybody comes to the door?

This is a bit hard to answer because your not saying what you are doing to try to prevent this but i will take a shot @ it
here it goes

Okay, most likely your dog is barking because they are trying to protect the house hold. I would put my dog on a leash (if you believe in choke chains - one of those) - your dog obviously has free run of the house & maybe you need that to stop until you can control this. YOu can repremand them by saying no and pulling back on the leash when htey bark... if that doesnt work you can try using a water ball.... when someone does walk by and the dog doesnt bark (& knows that someone is outside) praise your dog with treats and loving

Maybe I just think differently, but I appreciate the fact that my dog barks when someone knocks on my door. It's a warning to those outside "Hey a dog lives here, and it's his house". Max will bark when someone knocks, but before I open the door, I make him sit and stay- and reward him with a treat. I think by discouraging this all together is discouraging him from protecting his property.

TRY HAVING TREATS OUTSIDE YOUR DOOR. WHEN SOMEONE COMES TO THE DOOR HAVE THEM TAKE A TREAT. SHE ONLY GETS THE TREAT IF SHE IS SITTING AND NOT BARKING. YOU CAN PRACTICE WITH PEOPLE YOU KNOW