Board Thread:Questions and Answers/@comment-68.186.74.101-20150316093814/@comment-72.191.9.189-20150319044533

Usually as you go along the story the units you farm/collect will be able to help in leveling up. If not, the metal parades you get to access with the keys you get from the summoners hall administration office will help alot to level your units. this is the best bet as collecting units and fusing them gets more expensive as your units level goes up, and the  recieved-exp.-to-zel cost is terrible. you lose more money trying to level your units past level 30 with units you gain from the story, than in waiting for a metal parade and leveling substantially there.

an important thing to remember is that you should also try to level up your units bb burst if you get it to its six star form. this link is helpful http://bravefrontierglobal.wikia.com/wiki/Gameplay:Brave_Burst

you should wait til you get to six star form because once a unit moves up in rarity(4,5,6 star) because once you evolve it the only half the brave burst go with the unit to the next form.

one comment is that kagan desert is the better bang for yor buck for attack bb fodder, because you get more units and zel. good luck in leveling your units and once in six star form start leveling that bb guage ASAP. And it doesnt matter whether you fuse one unit at a time or five in one go, the chance will be the same to level up your bb, so i choose to do it one unit at a time. good luck leveling your units. happy huntings.