There are any number of specialized pet products, but really, any clippers that you use on your nails will work if they're sturdy and strong enough.
Just assume a stance of dominance and do it in good light so that you can see the darker roots and only clip the white excess.
Stance of dominance is crucial.
In my case, it was more of a weird hug/crouch of dominance - crouch on the cat so it can't move at all, then clip its claws. Otherwise, if it's got any limbs available to move, or its toothy head, it'll quickly let you know that its feet are off-limits for touching.
Pressed against the floor by something >10x its weight, and with severely-limited mobility as a result, all my cats would do was occasionally make a quiet and frustrated growl as their precious weaponry was dulled.
I'd always used a regular toenail clipper for them. Like Perknose said, stay away from the live tissue, and they'll be just fine.