Port to Alik’r Desert, type “x”(NA) or “+dolmen”(EU) in chat and you’ll be invited to join a group to grind dolmens (XP shared).
Craglorn Skyreach dungeons require a high level player to accompany you to a dungeon which spawns many hard to kill mobs but awards lots of XP (you may die but you’ll gain XP)
While doing the above, you should be in training gear as well as dunked an XP potion such as Psijic Ambrosia for maximum benefit