I assume you mean to level up experience points in ESO legitimately (Your in the minority here lol)
Personally i Skyshard hunt until level 10. Then go into CP campaign Imperial city. Level up solo, its fast and you get: keys, gold, exp, legerman, fighters guild experience plus getting the skyshards and mages books down there.
Everything everyone says is stupid... Spellscar grinding is the way to go. Sky-reach is only good because it's instanced but spellscar gives more XP. I leveled a toon in about 7 hours from 1 to 50
So when you level a new character you forget all the things you learned from playing previous characters? That's weird, I thought my memory was terrible.
Your saying that a DK plays exactly the same way as a NB or a Sorc or a Templar or Warden? Uses the exact same skills in the exact same order with the exact same buffs and class synergies?