You should feed your cat a diet of cat food made by a cat food company, it doesn't matter wether you feed wet or dry food, as both are specially made for cats. The food that you buy should have at least 50% animal protein ( cats are carnivores). The food should also have a moderate 20-40% fat with low carbs (1-2% calories).
When trying to figure out how much to feed your cat, as a basic rule of thumb, every pound of cat needs about 30 calories per day. For example, if a cat weighs 8 pounds, then you should feed it about 240 calories per day.