New to Smiting

I have 3 monks on my accounts that already have all (or nearly all) skills unlocked, would it be easier to learn with one of them in a particular location or start over from the beginning?

Why..... 3 monks?

If you have 3 then just choose the one with the most smiting skills and play through some areas with a smiting build until you get the hang of it.

If you are referring to 600/Smite smiting, then don't worry. It is the easiest thing in the world. All you do is slap on 4 enchantments (Retribution, Holy Wrath, Life Attunement/Balthazar's Spirit and Vital Blessing) and watch numbers fly, with the occasional BiP or Rez.

If you mean actual smiting, it's not hard but don't count on getting into 99% of pick up groups, because almost everyone expects a Monk to be a healer, and to lesser extents, protection/bonder.