4. Remove The Head Or Destroy The Brain
Always, always, always. Most experts recommend a good old-fashioned decapitation, since the impulses which inform a zombies actions tend to be echoes of activity governed by the medulla oblongata - breathing, swallowing, monitoring heart rates, and that sort of thing. (The debate as to whether zombies actually need to breathe/pump blood/swallow continues to rage, but if were taking Night Of The Living Dead zombies as our ur-text then they pretty clearly do, as that scene where Karen eats her dad shows in extreme clarity.) The problem is that that bit of the brain is right down at the back of the head near the spinal cord, which is a fairly tricky place to target accurately and repeatedly. Just bashing the zombie about until enough brain damage has been caused to that area to incapacitate it could take ages (unless its bones have softened sufficiently over the weeks in which its been decomposing, or if you were just concerned with ruining the zombies ability to construct and intellectually interrogate complex abstract concepts) so take a sabre to the thing and slice it to bits.