STOP MARKING THE TERRITORY
Many cat pet owners do not have problems with 'potty training' and most of the times, these gentle creatures can get very well behaved in this respect. They are known to literally hold it in until they get to their designated area and do their thing at the place where they know they need to do it.
As we all know, both humans and pet animals are creatures of habit when it comes to physiological needs, so there won't be any problems to train the cat pets for having good habits into using the litter box. But it can happen as well for some of these creatures to choose other areas for their 'littering' needs and this must be also an issue for you, since you read this article.
Or maybe you plan to buy a cat pet and want to be more informed on any issues that you can encounter with while owning a cat. Regardless of the situation, you should know that it might happen for cats to pee outside the designated area, and when this happens you want to know what the solution is.
If you catch your cat peeing on your furniture, you should give her more reasons to make her want use the litter box. First of all, cats are very clean, and they want to have their waste material as far as possible from their living area. This is why they tend to dig a hole and then leave the waste in there to have it buried once they are done.
Their need to stay clean can be the reason to make them want use the litter box. Once this area is not ensuring them the cleanliness they are after, they will look for another place to pee. So, when you notice that your cat releases her waste in another place than the box, it means that she is not satisfied with the state that the box is in.
So, the first thing to do is checking for this area and have it cleaned as soon as possible. Once there is no clean place for your cat to dig, then this box becomes unwelcoming to her, and she will plan to find some other place to offer her what her nature requires - more cleanliness. If she still insists in peeing on the furniture, then a good idea would be to have this furniture sprayed with vinegar which strong smell will chase away the cat.