Just scream OWIE!! really loud, give her a surprise...but NEVER ever hit her,also you need to get her some toys, and if shes clawing at stuff..she needs a scratching post. Also go to a petshop and you can buy a bitter spray that makes the cat not want to bit or go near your furnture. just make whatever shes bitting taste horrible :P

How old is the cat? Kittens go though a stage of pretty rough play, then they calm down some. Be sure you do have a good selection of toys for the kidder-cat, and also a scratching post. If you cat has nails, simply trim them, if you are worried about doing it, watch your Vet do it the first time, so you can see how much to clip off. Take care that YOU are not accidentally over stimulating the cat when you play, never use your hands as "toys." Only use toys to play with the cat. You can also consider getting a second cat. But it's always a period of adjustment for most cats to become "friends." We have 4 now, plus 2 dogs. I have had as many (years ago) as 7 cats. There is usually ONE that is rather a loner and would prefer that all other animals in the house be flushed down the toilet while still small enough to go down. But the rest all either totally love each other, or at the least, seem to enjoy playing off and on and will sometimes sleep cuddling together. Oddly enough the Females seem to have more attitude, the males seem to be willing to be buddies with males and willing females...ALL are neutered or spayed...and if YOUR cat is not yet...think about doing it if the cat is at least 5/6 months old.

When he goes to bite or scratch anything just give a loud sharp "Eh!" Learned that on "It's Me or the Dog" on Animal Planet.