Keep your windows screened at all times
Never assume that your kitty will be able to keep her balance on the window sill. Even the most agile of cats is bound to take a dangerous fall given enough trips to an unsecured window sill.
Always keep your cat ID'ed
You never know when your indoors-only cat will somehow get outside unsupervised. A cat collar with a clear ID tag that contains your name, phone number and a request to call that number if the cat is ever found outdoors, can truly save your cat's life and bring her back to you.
Triple check appliances where your cat may hide
Stories of cats caught in a washing machine or a dryer aren't just urban legends. Don't allow these appliances to become playing or resting areas. Keep their doors shut when not in use. And when you do use them, always triple check before running them!
Keep sharp utensils away from your cat's reach
A sharp knife can cut a curious tongue or paw, if left on the table or counter, still covered in tempting gravy.
Clear your house of anything that your cat might ingest
Hobbies that involve threads, needles, glue and small pieces can turn your home into a kitty minefield. Especially when dealing with active kittens, make sure that anything that might be ingested is out of reach.
Keep your toilet lid closed when not in use
If you have a kitten in your home, you could be saving her from jumping in and drowning. An older cat may be tempted to drink from the toilet water. Not only gross, but a risk of ingesting some of the disinfectants used in toilets.
Remove poisonous plants
Check lists of plants that are toxic to cats and simply take those out of your home. While not all cats nibble on greenery, it's best to avoid the risk, especially when bringing home a new cat or kitten.
Bundle all cords
Chewing an electrical cord can be fatal, and pulling on it may bring down an appliance that could injure your cat. Lamps can be strangulation hazards. or tie them off out of reach.
Keep garbage secure
Garbage with dangerous items such as bones and sharp tins in a trash can with a sturdy lid and latch. Plastic bags are as dangerous for cats as they are for small children so make sure you securely stow your plastic bags or keep them in a sealed recycle bin.