I might be yelled at for this later >~< I know this is pretty old but I have some tips.
Okay first off the paws seem a little too big, but still in proportion to the body. The front left paw though bothers me. It looks like it's turning towards the right one and hanging off the leg. Fix the angle a little if you draw another cat in this position.
The legs are way to long. Cats are much shorter and more stout. And also like ~imgoodatdrawing said, the cat needs to be longer. The tail looks fine but it could be a little more relaxed. The body is too wide to me. Some cats are buff but not this buff. It should be thinner. The chest looks flat, near the right leg. Puff it out a little.
Oh my gosh... the head... *.* Is perfect. I honestly can't draw one as well as you did. The only problems I see is that the eyes don't have pupils in them and the ears are a little big. Here's a picture of a cat to give you an little idea of how to improve on the body. [link] It isn't much or a great picture but it's something. Don't look at the head please...
I know that if you keep practicing, you will improve! You've gone so far! Don't give up!