How can I get a dog and a cat to get along?

There is NO guarantee.  Even if the dog has lived with a cat or cats BEFORE - it does NOT mean the dog will accept a new cat, as it did the others it may have grown UP with.  I do not suggest you do this.  If you do proceed, a long slow gradual introduction with the dog on leash or muzzled for a  number of days - may be required & cat should have escape routes (like a small cat door the dog cannot go through) to a SAFE area.

The best thing to do is just not get the dog. Better safe than sorry.

It's simple.  You don't.  Why would you put your cat in the position of having to defend his territory?

i don't believe in mixing dogs and cats unless brought up together from a young age. There is a good chance the cat will spend his days trying to escape from the dog.