My very first move any time a cat is peeing outside of the litter box is a quick trip to the vet to check a urine sample for infection. Honestly, I firmly believe that a urinary tract infection is the number one medical reason that a cat would urinate in inappropriate spots and quite frankly I feel they are more common than purely behavioral reasons. I have only had one cat who ever urinated outside of the box that didn't have a medical reason, at least initially, and she was dealing with a major lifestyle change (new baby) and less than great litterbox upkeep while me and DH were also adjusting to this huge change. You need to see the vet about a possible UTI before you do anything else. Not only do you need to treat it promptly before it becomes a behavioral problem (cats with UTI's are painful and can develop an aversion to the litter box because they are painful when they are in it trying to pee and come to associate that location, litter, or box with pain). I did have one cat who had chronic urinary tract infections and while his urinary indiscretions started because of painful infections it got to the point where we had to retrain him to use the litterbox using medications and strict confinement to a large dog crate because they became behavioral.
