I too used to draw canines a lot, then I tried my hand at felines. The main thing is this with each type:
domestic/small cats: Very small noses with large ears and eyes. Their body is usually thick and their paws a tad small. They look better with large whiskers.
big cats: A thick nose, slightly smaller than a canines. Their body is big and thicker, their paws big as well, with slightly smaller eyes.
smaller big cats (such as cheetahs): Skinny body with smallish paws and a small head, their eyes and ears being proportionate to their head.
Hope this helped some ^^