How do you level Maplestory characters up faster

The fastest and easiest way to level up is to have someone leech you. This is the only good way to level up fast at high levels. You have to be in a party with someone level 120 or up in the final job and just stand near them while they kill enemies and you get party experience. The enemies have to be close to your level. Wizard jobs are best to leech because they have attacks that can hit all enemies on screen.
You can also buy a 2x exp card or use rep to temporarily give you 2x exp.