Kidney disease has many causes and can lead to your pet drinking more, urinating more (although there are other causes of these symptoms) or being off their food or vomiting. They may also become lethargic. If your pet has any of these symptoms a vet appointment is required. 
Some pets need prescription medications to help kidney disease progressing including if appropriate blood pressure controlling medications. Renal diets are also important which are lower in protein and often altered sodium, potassium and phosphorous levels too from usual life stage diets. Unlimited fresh water must also be available. Omega-3 fatty acids are also thought to be important by reducing inflammation in the kidney. Your vet can advise you on the best diet for the stage of kidney failure that you pet is at.