A dog climbing up on your couch can be a problem on several levels. You don't want to compete with your dog for a place to sit. You don't want your dog to inconvenience your guests by refusing to move when they want to sit down. Even if your dog is sneaky and only gets up on the couch when you are out of the house, it will leave behind both hair and its scent, which will cling to you when you sit down. Use a combination of barriers and training as home remedies to keep your dog off the furniture.
Barriers repel dogs from couches by either inconveniencing them or scaring them. Something as simple as a broomstick laid across the couch can keep your dog from climbing up. Magazines and books also keep dogs down. Spread aluminum foil across the length of the couch. Dogs don't like the way it sounds or feels so when they jump up onto it, they get back down again. The only problem with barriers is that they stop you from enjoying your couch and have to be moved every time you want to sit down.
Try modifying your dog's behavior to keep it off the couch. Give it its own bed in the living room, so it has someplace to go besides the couch. Create a bad association with the couch by filling a can half-full of pennies. Every time your dog gets on the couch, shake the can. The loud noise will startle your dog and drive it off the couch. Over time, you dog will associate the scary sound with the couch and avoid it altogether.
When working to train your dog to stay off the couch, it is helpful to keep a short leash attached to its collar. If you catch your dog on the couch, take the leash and lead it down, then lead the dog over to where you want it to be instead. It is easiest to keep a dog off the furniture if you never allow it on, rather than allowing it to get up occasionally. Dogs can't tell the difference between situations the way humans can and will get up on the couch when you don't want them there.