First thing is why does he get up there? Does it allow a better viewpoint/vantage? Is it an older dog who gets sore from lying on the floor?
Once your dog is accustomed to getting on a piece of furniture, it can be very hard to get them to stop. You can try getting a couch cover, you can try plastic on the couch or that plastic carpet protector with the little plastic pointy things on the bottom that'll deter the dog from lying on the couch. They make scat mats that produce a light electrical shock when you sit on them, but I just don't like those kinda things.
There's also a spray that keeps animals from chewing on shit, that may or may not work. It's called bitter apple but I dunno for keeping him off the couch, though. Same for other stuff to spray, dunno if you wanna it on your couch.
Another thing you may try is getting the dog it's own piece of furniture. For my male, he's had his own chair for years now. It's big enough for him to lay different ways comfortably (and heavy enough not to move when he jumps in and out of it - important) and it's right beside the couch so he always feels part of the pack. I have a nice blanket he's been using forever on the chair and he knows that's his spot. It will take time to train your dog to understand he can only use the chair or whatever. The easiest way to change an animals mind is to offer them an alternative. Remember, the offering a new piece of furniture wont' make a difference if you put it in a crappy place.
Another thing is called a Tattletale, I believe. It beeps and vibrates when the dog jumps on the couch hopefully scaring off the dog. Again, this doesn't actually solve the reasons why the dog gets up there which could be as simple as it's more fucking comfortable than the floor! So, again, be sure to provide an alternative. And remember, location, location, location.
I'm sure there are other tips I've forgotten. I'll post them later if and when I think of them. Otherwise, hopefully someone will add to this. Good luck. Let me know if you have any ?'s. I don't feel like rereading what I just typed. lol