The source is from here.

Start training at Henesys Hunting Ground for a bit in MapleStory.

Party'ing with someone helpfull, don't loot off of them, and have them do it for you, that's basically stealing (but of course if you have friends to train you, you can probably loot off them).

Go to the slime tree in Ellinia and train there, since you get 10 exp from slimes, if you even have NX get the dbl exp card, and lvl faster, You can also do Henesys PQ as well.

Rest for a bit because you probably played too much, then come back later(maple story mesos). Also doing all the quest available to you helps you lvl faster as well, but if you get them done before the lvl 15 quests are available then kill some slimes.

Once you reach 21 then you probably want to do KPQ up to 30, from 30 get your 2nd joband from 30-50 do the CPQ all the way, it's very easy to lvl here, the only thing you don't gain here is meso's, and you don't lose exp when you die either.

Doing a Trade Win, after lvl 40 you can do either a trade win, or just normal cpq. when you are at lvl 30(maple story mesos), you probably want to find a good friend that will help you because at 30, you are weak and mostly are miss's so you want to get some higher lvl then you to help you out.

From 51-70, I would recommend LMPQ, you get good items and you can sell, them and you can make meso's easily, if you play all day on LMPQ you can make over 1 mill meso's.

Then at 70, get your third job, and just train until you get to lvl 71, and from there you can do the Megatia PQ.