Buy a Holy Medicene from Item Gal, it boosts your experience.
There is no fastest way, there is only the way. Wait. It is possible that you can speed up the process by exercising, but the increase is negligible.
I would need to know what you want to plan, to advise on the fastest way to do it.
Running.
The fastest way a gibbon can get through the jungle is by jumping from branch to branch or going from vine to vine.
its the fastest way to get into the castle.
Do quests.
rare candy
The fastest way to level up is to grind, which is killing mobs that are your level until you level. This is a quick way, but.... is incredibly boring. I suggest doing quests, and buying a leveling guide which will help you level as fast as possible. Zygors guide is the best on the market.
Assuming your probably wanting to level to 80 now. Questing is the fastest way to level, if you aren't a fan of questing then you can level through AV after 60 which is about an hour longer.
there is no "fast" way to get to level 100 if you can even get to that level...im sure that you can only get to level 60-70 MAX
battle a guy in Leigon
play hard
ij
just fight and fight to fast level up
straight up SD
train them and enter them in competions
just keep training