I don't remember about other makers, but I know in RMVX the Hep file contains the battle formulas in a chapter. I would suggest you look at that to figure out balance.
For instance, it says that damage from a normal attack is:
(4*attacker's attack) - (2*defender's defence)
Balance is a hard part of making an RPG and there is no easy solution. Just know the formulas, adjust accordingly, do battle tests, and readjust.