AFAICT the fastest way ive found to level so far was just multiple questing on a single mob at a time, since joining the clan ive mixed it up with some GV parties/quests and guild/ clan quests. The problem is that its getting bloody hard to finish a level with only quests.... so you have to grind your ass off for up to 40% without any quests rewarding with extra xp
Choose your races starting zone and either Phillai or Caeldome (helpful to choose one that you prefer the mobs aesthetically or have some experience with) and grind the quests there - yes, you've got the backlog of lvl 1 - [current level] but these arent too back and can be quickly got through. Dont fail to neglect your other chosen zone though.
Still this isnt too bad, until you hit 45+ since the starting race zones merge and you lose the number of avaliable quests to you. Now its a case of "gotta suck it and see" - as the saying goes. Aside from that GV parties are the way forwards, although i should probably do the VGV/ VCC refills (LAZYYYYYY).
If you level off a quest, then yes the skill point gained will not show up - simply go kill a mob and itll appear ;p