1) chain whip
2) some people use loctite, some use grease; def use something, but not too much.
3) do this:
- line the threads with grease (or loctite)-- remember, not too much at all. the threads will be flush, so even a tiny bit will spread through.
- put the cog on nice and snug
- put the ring on nice and snug
- re-tighten the cog, simultaneously tigtening the lockring
- tighten the **** out of the lock ring; i've seen people tap the end of the lockring wrench with a mallot to get a bit more force, but that might be overkill.

-presto-