First you have to catch him, because some how he some 6th sense that tells him you want to trim his razor-sharp, surgical scalpels. Then you wrap him firmly in a blanket so he can't bite you or get in one last swipe with his untrimmed paw. Reach in the blanket and pull out a leg, any leg, front or back, the point is to get a nail descalpelized.
Then quick grab his paw and clip. If you are lucky you might get a whole paw done or just one nail before he sucks it back in. We find that about four attempts is all we get before he turns into a Tasmanian Devil and you have to put him down. Wait a couple weeks, this cat has a long memory, until his guard is down a little bit and try for the rest of them.