I know you're not really listening but

a) do quests they give 10-20k xp when in your 20s/30s - that's 100s kills in 1 quest return

b) if you tag a mob but kill it with other groups you get less xp (check your combat log/experiment)

c) don't be discouraged by ppl saying it takes "x minutes"/hours to get to level Y and it takes you a lot longer
c.1) it's normal to take longer the bigger the group
c.2) I know wow fairly well having leveled 2 70s and a few alts to 50/60s before starting multi boxing and my first team took me 4 days 12h /played to get to 60 (not 2 days or whatever ppl do) - my new team took 8hours /played to get to 15; etc...

d) learn the game first: take 2 raf'ed guys (so its fast) and level those 2 to at least 60 to figure out how the game is before wasting time 26x. Or at least do 1 5x team and get it to l30 and learn from that for you next teams...