You will need:
As far as claw trimmers go, I really like these cat claw clippers.
a towel or old blanket (optional)
- styptic powder (optional)
I've had the same pair for years and they're great for two reasons:
very sharp, and they cut quickly with not a ton of time spent lining them up
really quiet, unlike larger spring loaded trimmers, so you don't have any loud noises to spook the cat.
Styptic powder is a good thing to have around if this is your first time trimming the cat's claws, or if you have an animal that fusses and moves around a lot while trimming. It will help stop the bleeding if you trim too far down. Cornstarch is a great substitute if you don't have styptic powder on hand.