The real trick to giving a cat a pill:
From my vet in part, with refinements by yours truly:
1.grab them by a BIG handful of scruff, hard! with your
nondominant hand, on a carpeted surface, and pull them forward. Naturally, they will dig all four claws into the carpet and open their mouths to protest.
2. with your dominant hand, stuff the pill as
far down their throat as possible3. grab their mouth and hold it shut, again with the dominant hand, while continuing to provide traction with the nondominant hand, so they don't tear you a new one.
4. stroke their adam's apple with your dominant hand's thumb until you hear a gulp. Then let go very fast.
They will run off. Let them go be outraged at the nerve of the help and give them a nice treat when they come out.

@spacial: they do make tonics that are meant to be tasty-also ones meant to be put on the paws, so the cats are forced to groom themselves and lick it off whether they like it or not.
Unfortunately, I've never been able to get hiding pills to work for cats-dogs, though-wrap it in cheese, and gobble-gobble. My one dog gets pretty much daily allergy meds at this point, and he's SO happy about it!
(We are overrun with cats ATM, by the way...seven! all rescued...need to work on rehoming the ones that we can-one sprays, even though neutered, and one refuses to come inside....)