lol eso is a big grinding game on higher levels, you know although you have options to do some quests (Ether Saga Online Gold), which you will eventually run out of fast, you can do bulletin board quests you suppose but other than that it turns into a grind fest of possessing.
edit and if you thinking getting 0.1% per kill is low, wait till you reach 100, but yeah oh and once you hit level 25, get your ranger aoe called Surprise Assault and aoe to level grind, its the best and most effective way of leveling, also kite the mobs, if you don't know what that means is run, hit, run some more hit, make it so they do not hit you as much, you will only need to do this when you AoE kite mobs and when you have like 10 mobs on you.
Edit again lol, also there are many ways to level. the best most effectively way to level at high level or mid levels and up, is to do the double exp bulletin board mobs, for example you will find an announcement for like, haunten type mobs on bulletin board quests, when you turn in a quest from bulletin board that gave like 200k exp, it will be 400k exp instead. That comes to the ending, hope it could help you.