If you find a stray but cannot keep it, try socializing it before finding it another home. Train it to use a litter box and to be petted and held, since socialized kitties stand a better chance of being adopted.read more
To your cat, your home is like an urban jungle, and that includes all your furniture and other accessible goodies. Cats are quite practical, however, so the furniture likely holds some function for your feline: easier transportation (such as marching over a coffee table to get to a chair), sleeping area (as on a comfy sofa) or surface for scratching claws.
To keep your cat off any item, make it unattractive to your pet and provide a better alternative. Scratching on a couch or wooden furniture is probably the worst kitty offense; the most important preventive measure in this case is to regularly trim your cat's claws. This helps your pet, since claws can get caught in material. It'll help you too, by preventing couch and curtain rips.
Cats hate the feel and smell of tinfoil and sticky tape, so you can try placing these on areas your cat targets. If possible, spray an odor-neutralizing solution -- sold at pet stores. Since cats usually return to places where they've left their scent, the sprays might throw them off. If you need to protect the fabric of a chair or couch, place a blanket over the furniture temporarily and then spray with the odor neutralizer or a citrus-scented spray, such as one containing orange oil. Cats usually hate citrus smells -- the volatile oils in the fruit rind evolved, in part, to deter curious and hungry animals.
Finally, consider purchasing a cat tree that offers good places for claw scratching, as well as one or more cubbyholes or perches. Place the tree in an area frequented by your cat and sprinkle it with catnip. Make sure the tree is stable and will not tip over when your cat hops on it.