Without knowing your characters level, class and build it is difficult to give a definitive answer. Whether you are P2P, F2P, play solo or in groups also makes a difference. Even then, you will get many different opinions on where the best place to level is. Besides fighting monsters, you can gain experience through fighting Training dopples as well as quests including Head hunter Class specific guides as well as Experimental builds can be found on the Dofus Wiki.